Home |
Search |
Today's Posts |
#1
Posted to microsoft.public.excel.worksheet.functions
|
|||
|
|||
Matrix multiplication using sumproduct
In some engineering calculations, we have multiplication of matrices or
matrices and vectors. It is defined as follows by an example: [A]= 2 3 5 (an array of 3 rows and 3 columns) 2 4 6 1 -2 4 [b]= 6 (an array of 3 rows and 1 column) -5 1 [A] *[b] = 2*6+3*(-5)+5*1 2*6+4*(-5)+6*1 1*6+(-2)*(-5)+4*1 [A] *[b] = 2$B!!(B(an array of 3 rows and 1 column) -2 20 For long time, I was performing this task by simple multiplication and summation. Recently through this ng, I came to know about SUMPRODUCT command and thought of writing a command to do matrices multiplication. I came to following command which satisfies me. If you know any better way for matirces multiplication, let me know. In real engineering problems sometimes we have to perform this task for very big matrices like (100 rows by 100 columns, and even bigger ones) for calculation of inverse of a matrix, which makes it very time consuming. For this reason approximate methods are introduced. I was wondering if these calculations will be time-consuming in Excel or not. [A] from a1 to c3 [b] from d1 to d3 [A]*[b] from e1 to e3 In e1 I enter: sumproduct(a1:c1,transpose(d$1:d$3)) entered as array formula (CSE) drag the top formula to e2 and e3. |
#2
Posted to microsoft.public.excel.worksheet.functions
|
|||
|
|||
Matrix multiplication using sumproduct
Is MMULT a built-in function or add-in one?
"JMB" wrote in message ... Try selecting E1:E3, enter =MMULT($A$1:$C$3,$D$1:$D$3) confirmed w/CSE "Rasoul Khoshravan" wrote: In some engineering calculations, we have multiplication of matrices or matrices and vectors. It is defined as follows by an example: [A]= 2 3 5 (an array of 3 rows and 3 columns) 2 4 6 1 -2 4 [b]= 6 (an array of 3 rows and 1 column) -5 1 [A] *[b] = 2*6+3*(-5)+5*1 2*6+4*(-5)+6*1 1*6+(-2)*(-5)+4*1 [A] *[b] = 2 (an array of 3 rows and 1 column) -2 20 For long time, I was performing this task by simple multiplication and summation. Recently through this ng, I came to know about SUMPRODUCT command and thought of writing a command to do matrices multiplication. I came to following command which satisfies me. If you know any better way for matirces multiplication, let me know. In real engineering problems sometimes we have to perform this task for very big matrices like (100 rows by 100 columns, and even bigger ones) for calculation of inverse of a matrix, which makes it very time consuming. For this reason approximate methods are introduced. I was wondering if these calculations will be time-consuming in Excel or not. [A] from a1 to c3 [b] from d1 to d3 [A]*[b] from e1 to e3 In e1 I enter: sumproduct(a1:c1,transpose(d$1:d$3)) entered as array formula (CSE) drag the top formula to e2 and e3. |
#3
Posted to microsoft.public.excel.worksheet.functions
|
|||
|
|||
Matrix multiplication using sumproduct
Try selecting E1:E3, enter
=MMULT($A$1:$C$3,$D$1:$D$3) confirmed w/CSE "Rasoul Khoshravan" wrote: In some engineering calculations, we have multiplication of matrices or matrices and vectors. It is defined as follows by an example: [A]= 2 3 5 (an array of 3 rows and 3 columns) 2 4 6 1 -2 4 [b]= 6 (an array of 3 rows and 1 column) -5 1 [A] *[b] = 2*6+3*(-5)+5*1 2*6+4*(-5)+6*1 1*6+(-2)*(-5)+4*1 [A] *[b] = 2 (an array of 3 rows and 1 column) -2 20 For long time, I was performing this task by simple multiplication and summation. Recently through this ng, I came to know about SUMPRODUCT command and thought of writing a command to do matrices multiplication. I came to following command which satisfies me. If you know any better way for matirces multiplication, let me know. In real engineering problems sometimes we have to perform this task for very big matrices like (100 rows by 100 columns, and even bigger ones) for calculation of inverse of a matrix, which makes it very time consuming. For this reason approximate methods are introduced. I was wondering if these calculations will be time-consuming in Excel or not. [A] from a1 to c3 [b] from d1 to d3 [A]*[b] from e1 to e3 In e1 I enter: sumproduct(a1:c1,transpose(d$1:d$3)) entered as array formula (CSE) drag the top formula to e2 and e3. |
#4
Posted to microsoft.public.excel.worksheet.functions
|
|||
|
|||
Matrix multiplication using sumproduct
Seems to be built in (I'm using XL 2000 - wouldn't think they'd take it out
of subsequent versions, though). "Rasoul Khoshravan" wrote: Is MMULT a built-in function or add-in one? "JMB" wrote in message ... Try selecting E1:E3, enter =MMULT($A$1:$C$3,$D$1:$D$3) confirmed w/CSE "Rasoul Khoshravan" wrote: In some engineering calculations, we have multiplication of matrices or matrices and vectors. It is defined as follows by an example: [A]= 2 3 5 (an array of 3 rows and 3 columns) 2 4 6 1 -2 4 [b]= 6 (an array of 3 rows and 1 column) -5 1 [A] *[b] = 2*6+3*(-5)+5*1 2*6+4*(-5)+6*1 1*6+(-2)*(-5)+4*1 [A] *[b] = 2 (an array of 3 rows and 1 column) -2 20 For long time, I was performing this task by simple multiplication and summation. Recently through this ng, I came to know about SUMPRODUCT command and thought of writing a command to do matrices multiplication. I came to following command which satisfies me. If you know any better way for matirces multiplication, let me know. In real engineering problems sometimes we have to perform this task for very big matrices like (100 rows by 100 columns, and even bigger ones) for calculation of inverse of a matrix, which makes it very time consuming. For this reason approximate methods are introduced. I was wondering if these calculations will be time-consuming in Excel or not. [A] from a1 to c3 [b] from d1 to d3 [A]*[b] from e1 to e3 In e1 I enter: sumproduct(a1:c1,transpose(d$1:d$3)) entered as array formula (CSE) drag the top formula to e2 and e3. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Matrix Problem | Excel Discussion (Misc queries) | |||
Matrix Multiplication | Excel Discussion (Misc queries) | |||
Matrix Multiplication | Excel Worksheet Functions | |||
matrix multiplication | Excel Worksheet Functions | |||
Matrix multiplication with empty cells | Excel Worksheet Functions |