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Increment for or do while loop by 0.001 (not 1)
What I am trying to do: increment for loop or do while loop by 0.001
---------------------- My for loop (I don't know how to increment by 0.001, this code just increments by 1): ---------------------- For X = 0 To 10 'For X between 0 and 10 incremented by 0.001 For Y = 0 To 10 'For X between 0 and 10 incremented by 0.001 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Next 'End inner for loop (Y loop) Next 'End outer for loop (X loop) ---------------------- My do while loop (I tried incrementing by 0.001, but the answer is not what I want): ---------------------- Do While X <= 10 Do While Y <= 10 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function with new X and Y value If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Y = Y + 0.001 If Y 10 Then Exit Do Loop X = X + 0.001 If X 10 Then Exit Do Loop ---------------------- My Question for the do while loop: why am I not getting an xmax = 0.215 and ymax =10.000? I think this is these are the correct answers. ---------------------- |
Increment for or do while loop by 0.001 (not 1)
this should get you started:
Sub abc() Dim i As Double Dim sStr As String For i = 1 To 2 Step 0.1 sStr = sStr & i & vbNewLine Next MsgBox sStr End Sub -- Regards, Tom Ogilvy "Han" wrote in message ups.com... What I am trying to do: increment for loop or do while loop by 0.001 ---------------------- My for loop (I don't know how to increment by 0.001, this code just increments by 1): ---------------------- For X = 0 To 10 'For X between 0 and 10 incremented by 0.001 For Y = 0 To 10 'For X between 0 and 10 incremented by 0.001 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Next 'End inner for loop (Y loop) Next 'End outer for loop (X loop) ---------------------- My do while loop (I tried incrementing by 0.001, but the answer is not what I want): ---------------------- Do While X <= 10 Do While Y <= 10 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function with new X and Y value If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Y = Y + 0.001 If Y 10 Then Exit Do Loop X = X + 0.001 If X 10 Then Exit Do Loop ---------------------- My Question for the do while loop: why am I not getting an xmax = 0.215 and ymax =10.000? I think this is these are the correct answers. ---------------------- |
Increment for or do while loop by 0.001 (not 1)
Tom,
I have noticed that using something like : Dim i As Double For i = 1 To 10 Step 0.1 Debug.Print i Next you cannot use : If i=6.2 Then because of accuracy issues. e.g. ............ 5.8 5.9 6 6.1 6.19999999999999 6.29999999999999 6.39999999999999 .......... Using a Currency type avoids this . NickHK P.S. Seems strange that if you add a line "If i 6 Then Stop" in the loop, then in the immediate window "?i+0.1" the result is 6.2 exactly. But "?i+0.1=6.2" shows False. Confused ? So a For/Next loop like this is not really adding 0.1 each time, but using integers really then scaling the counter ? "Tom Ogilvy" wrote in message ... this should get you started: Sub abc() Dim i As Double Dim sStr As String For i = 1 To 2 Step 0.1 sStr = sStr & i & vbNewLine Next MsgBox sStr End Sub -- Regards, Tom Ogilvy "Han" wrote in message ups.com... What I am trying to do: increment for loop or do while loop by 0.001 ---------------------- My for loop (I don't know how to increment by 0.001, this code just increments by 1): ---------------------- For X = 0 To 10 'For X between 0 and 10 incremented by 0.001 For Y = 0 To 10 'For X between 0 and 10 incremented by 0.001 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Next 'End inner for loop (Y loop) Next 'End outer for loop (X loop) ---------------------- My do while loop (I tried incrementing by 0.001, but the answer is not what I want): ---------------------- Do While X <= 10 Do While Y <= 10 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function with new X and Y value If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Y = Y + 0.001 If Y 10 Then Exit Do Loop X = X + 0.001 If X 10 Then Exit Do Loop ---------------------- My Question for the do while loop: why am I not getting an xmax = 0.215 and ymax =10.000? I think this is these are the correct answers. ---------------------- |
Increment for or do while loop by 0.001 (not 1)
That is because 0.1, 0.001, and the vast majority of other terminating
decimal fractions are non-terminating binary fractions that can only be approximated. Using the Currency type does not avoid the issue altogether, it just restricts it to where you would expect it. For intance, presumably you would understand why Dim i As Currency i=1/3 i=1-3*i does not have i as zero at the end. Jerry "NickHK" wrote: Tom, I have noticed that using something like : Dim i As Double For i = 1 To 10 Step 0.1 Debug.Print i Next you cannot use : If i=6.2 Then because of accuracy issues. e.g. ............ 5.8 5.9 6 6.1 6.19999999999999 6.29999999999999 6.39999999999999 .......... Using a Currency type avoids this . NickHK P.S. Seems strange that if you add a line "If i 6 Then Stop" in the loop, then in the immediate window "?i+0.1" the result is 6.2 exactly. But "?i+0.1=6.2" shows False. Confused ? So a For/Next loop like this is not really adding 0.1 each time, but using integers really then scaling the counter ? "Tom Ogilvy" wrote in message ... this should get you started: Sub abc() Dim i As Double Dim sStr As String For i = 1 To 2 Step 0.1 sStr = sStr & i & vbNewLine Next MsgBox sStr End Sub -- Regards, Tom Ogilvy "Han" wrote in message ups.com... What I am trying to do: increment for loop or do while loop by 0.001 ---------------------- My for loop (I don't know how to increment by 0.001, this code just increments by 1): ---------------------- For X = 0 To 10 'For X between 0 and 10 incremented by 0.001 For Y = 0 To 10 'For X between 0 and 10 incremented by 0.001 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Next 'End inner for loop (Y loop) Next 'End outer for loop (X loop) ---------------------- My do while loop (I tried incrementing by 0.001, but the answer is not what I want): ---------------------- Do While X <= 10 Do While Y <= 10 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function with new X and Y value If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Y = Y + 0.001 If Y 10 Then Exit Do Loop X = X + 0.001 If X 10 Then Exit Do Loop ---------------------- My Question for the do while loop: why am I not getting an xmax = 0.215 and ymax =10.000? I think this is these are the correct answers. ---------------------- |
Increment for or do while loop by 0.001 (not 1)
Thank you everyone for all your input. Using "step" and "currency"
worked for my application. Jerry W. Lewis wrote: That is because 0.1, 0.001, and the vast majority of other terminating decimal fractions are non-terminating binary fractions that can only be approximated. Using the Currency type does not avoid the issue altogether, it just restricts it to where you would expect it. For intance, presumably you would understand why Dim i As Currency i=1/3 i=1-3*i does not have i as zero at the end. Jerry "NickHK" wrote: Tom, I have noticed that using something like : Dim i As Double For i = 1 To 10 Step 0.1 Debug.Print i Next you cannot use : If i=6.2 Then because of accuracy issues. e.g. ............ 5.8 5.9 6 6.1 6.19999999999999 6.29999999999999 6.39999999999999 .......... Using a Currency type avoids this . NickHK P.S. Seems strange that if you add a line "If i 6 Then Stop" in the loop, then in the immediate window "?i+0.1" the result is 6.2 exactly. But "?i+0.1=6.2" shows False. Confused ? So a For/Next loop like this is not really adding 0.1 each time, but using integers really then scaling the counter ? "Tom Ogilvy" wrote in message ... this should get you started: Sub abc() Dim i As Double Dim sStr As String For i = 1 To 2 Step 0.1 sStr = sStr & i & vbNewLine Next MsgBox sStr End Sub -- Regards, Tom Ogilvy "Han" wrote in message ups.com... What I am trying to do: increment for loop or do while loop by 0.001 ---------------------- My for loop (I don't know how to increment by 0.001, this code just increments by 1): ---------------------- For X = 0 To 10 'For X between 0 and 10 incremented by 0.001 For Y = 0 To 10 'For X between 0 and 10 incremented by 0.001 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Next 'End inner for loop (Y loop) Next 'End outer for loop (X loop) ---------------------- My do while loop (I tried incrementing by 0.001, but the answer is not what I want): ---------------------- Do While X <= 10 Do While Y <= 10 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function with new X and Y value If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Y = Y + 0.001 If Y 10 Then Exit Do Loop X = X + 0.001 If X 10 Then Exit Do Loop ---------------------- My Question for the do while loop: why am I not getting an xmax = 0.215 and ymax =10.000? I think this is these are the correct answers. ---------------------- |
Increment for or do while loop by 0.001 (not 1)
Thank you everyone for you input. Using "step" and "currency" works
for my application. It runs slow (takes a few minutes), but it functions. Jerry W. Lewis wrote: That is because 0.1, 0.001, and the vast majority of other terminating decimal fractions are non-terminating binary fractions that can only be approximated. Using the Currency type does not avoid the issue altogether, it just restricts it to where you would expect it. For intance, presumably you would understand why Dim i As Currency i=1/3 i=1-3*i does not have i as zero at the end. Jerry "NickHK" wrote: Tom, I have noticed that using something like : Dim i As Double For i = 1 To 10 Step 0.1 Debug.Print i Next you cannot use : If i=6.2 Then because of accuracy issues. e.g. ............ 5.8 5.9 6 6.1 6.19999999999999 6.29999999999999 6.39999999999999 .......... Using a Currency type avoids this . NickHK P.S. Seems strange that if you add a line "If i 6 Then Stop" in the loop, then in the immediate window "?i+0.1" the result is 6.2 exactly. But "?i+0.1=6.2" shows False. Confused ? So a For/Next loop like this is not really adding 0.1 each time, but using integers really then scaling the counter ? "Tom Ogilvy" wrote in message ... this should get you started: Sub abc() Dim i As Double Dim sStr As String For i = 1 To 2 Step 0.1 sStr = sStr & i & vbNewLine Next MsgBox sStr End Sub -- Regards, Tom Ogilvy "Han" wrote in message ups.com... What I am trying to do: increment for loop or do while loop by 0.001 ---------------------- My for loop (I don't know how to increment by 0.001, this code just increments by 1): ---------------------- For X = 0 To 10 'For X between 0 and 10 incremented by 0.001 For Y = 0 To 10 'For X between 0 and 10 incremented by 0.001 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Next 'End inner for loop (Y loop) Next 'End outer for loop (X loop) ---------------------- My do while loop (I tried incrementing by 0.001, but the answer is not what I want): ---------------------- Do While X <= 10 Do While Y <= 10 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function with new X and Y value If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Y = Y + 0.001 If Y 10 Then Exit Do Loop X = X + 0.001 If X 10 Then Exit Do Loop ---------------------- My Question for the do while loop: why am I not getting an xmax = 0.215 and ymax =10.000? I think this is these are the correct answers. ---------------------- |
Increment for or do while loop by 0.001 (not 1)
I fully expected such approximation, but seemed strange why it did not
become apparent until 6.2 But also the loop cannot really be 1+0.1+0.1........+0.1 because then "i" would fixed at maximum 1 decimal place NickHK "Jerry W. Lewis" ... That is because 0.1, 0.001, and the vast majority of other terminating decimal fractions are non-terminating binary fractions that can only be approximated. Using the Currency type does not avoid the issue altogether, it just restricts it to where you would expect it. For intance, presumably you would understand why Dim i As Currency i=1/3 i=1-3*i does not have i as zero at the end. Jerry "NickHK" wrote: Tom, I have noticed that using something like : Dim i As Double For i = 1 To 10 Step 0.1 Debug.Print i Next you cannot use : If i=6.2 Then because of accuracy issues. e.g. ............ 5.8 5.9 6 6.1 6.19999999999999 6.29999999999999 6.39999999999999 .......... Using a Currency type avoids this . NickHK P.S. Seems strange that if you add a line "If i 6 Then Stop" in the loop, then in the immediate window "?i+0.1" the result is 6.2 exactly. But "?i+0.1=6.2" shows False. Confused ? So a For/Next loop like this is not really adding 0.1 each time, but using integers really then scaling the counter ? "Tom Ogilvy" wrote in message ... this should get you started: Sub abc() Dim i As Double Dim sStr As String For i = 1 To 2 Step 0.1 sStr = sStr & i & vbNewLine Next MsgBox sStr End Sub -- Regards, Tom Ogilvy "Han" wrote in message ups.com... What I am trying to do: increment for loop or do while loop by 0.001 ---------------------- My for loop (I don't know how to increment by 0.001, this code just increments by 1): ---------------------- For X = 0 To 10 'For X between 0 and 10 incremented by 0.001 For Y = 0 To 10 'For X between 0 and 10 incremented by 0.001 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Next 'End inner for loop (Y loop) Next 'End outer for loop (X loop) ---------------------- My do while loop (I tried incrementing by 0.001, but the answer is not what I want): ---------------------- Do While X <= 10 Do While Y <= 10 Fnew = X * Y * Exp(1 - 2 * X) * Sin(Y - X) * (1 - Y ^ 2) 'Given function with new X and Y value If Fold <= Fnew Then 'If previous value of function is less than current value of f then... xmax = X 'Store value of X for max value of F ymax = Y 'Store value of y for max value of F Fold = Fnew 'Update the function End If 'End if statement Y = Y + 0.001 If Y 10 Then Exit Do Loop X = X + 0.001 If X 10 Then Exit Do Loop ---------------------- My Question for the do while loop: why am I not getting an xmax = 0.215 and ymax =10.000? I think this is these are the correct answers. ---------------------- |
Increment for or do while loop by 0.001 (not 1)
Excel displays a maximum of 15 digits, but it takes 17 digits to uniquely
specify a binary floating point value. The discrepancys begin at 1.2, but don't accumulate sufficiently to be visible in the 15th digit until after 6. You can see this by changing your output statement to Debug.Print i - Round(10 * i, 0) / 10 or by using the D2D function from http://groups.google.com/group/micro...06871cf92f8465 Jerry "NickHK" wrote: I fully expected such approximation, but seemed strange why it did not become apparent until 6.2 But also the loop cannot really be 1+0.1+0.1........+0.1 because then "i" would fixed at maximum 1 decimal place NickHK "Jerry W. Lewis" ... That is because 0.1, 0.001, and the vast majority of other terminating decimal fractions are non-terminating binary fractions that can only be approximated. Using the Currency type does not avoid the issue altogether, it just restricts it to where you would expect it. For intance, presumably you would understand why Dim i As Currency i=1/3 i=1-3*i does not have i as zero at the end. Jerry "NickHK" wrote: Tom, I have noticed that using something like : Dim i As Double For i = 1 To 10 Step 0.1 Debug.Print i Next you cannot use : If i=6.2 Then because of accuracy issues. e.g. ............ 5.8 5.9 6 6.1 6.19999999999999 6.29999999999999 6.39999999999999 .......... Using a Currency type avoids this . NickHK P.S. Seems strange that if you add a line "If i 6 Then Stop" in the loop, then in the immediate window "?i+0.1" the result is 6.2 exactly. But "?i+0.1=6.2" shows False. Confused ? So a For/Next loop like this is not really adding 0.1 each time, but using integers really then scaling the counter ? |
Increment for or do while loop by 0.001 (not 1)
Han,
I got this to work by doing some mods...it works for me with the step 0.001 but then you have to round the xmax and ymax as they come out with 0.214999999.. and 9.9999... RUn time for me with the changes was 1 minute 08 secs I am not sure what your application is for this ...but to speed things up..I would think ( if it is possible) to try and limit the ranges you must run this over. Anyway hope this helps.... if you want my form with the code ..just shoot me a email. Steve |
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