naginterfaces.library.matop.real_​gen_​matmul

naginterfaces.library.matop.real_gen_matmul(b, c, opt)

real_gen_matmul returns with the result of the multiplication of two matrices $B$ and $C$ in the matrix $A$, with the option to overwrite $B$ or $C$.

For full information please refer to the NAG Library document for f01ck

https://www.nag.com/numeric/nl/nagdoc_29.3/flhtml/f01/f01ckf.html

Parameters

bfloat, array-like, shape $(n,m)$

The $n\times m$ matrix $B$.

cfloat, array-like, shape $(m,p)$

The $m\times p$ matrix $C$.

optint

The value of $opt$ determines which array is to contain the final result.

$opt=1$

$a$ must be distinct from $b$ and $c$ and, on exit, contains the result. $b$ and $c$ need not be distinct in this case.

$opt=2$

$b$ must be distinct from $c$ and on exit, contains the result. $a$ is not used in this case and need not be distinct from $b$ or $c$.

$opt=3$

$c$ must be distinct from $b$ and on exit, contains the result. $a$ is not used in this case and need not be distinct from $b$ or $c$.

Returns

afloat, ndarray, shape $(n,p)$

If $opt=1$, $a$ contains the result of the matrix multiplication.

bfloat, ndarray, shape $(n,m)$

If $opt=2$, $b$ contains the result of the multiplication.

cfloat, ndarray, shape $(m,p)$

If $opt=3$, $c$ contains the result of the multiplication.

Raises

NagValueError

(errno $1$)

On entry, $p=⟨value⟩$.

Constraint: $p\ge 1$.

(errno $1$)

On entry, $n=⟨value⟩$.

Constraint: $n\ge 1$.

(errno $1$)

On entry, $m=⟨value⟩$.

Constraint: $m\ge 1$.

(errno $2$)

On entry, $m=⟨value⟩$ and $p=⟨value⟩$.

Constraint: if $opt=2$, $m=p$.

(errno $3$)

On entry, $n=⟨value⟩$ and $m=⟨value⟩$.

Constraint: if $opt=3$, $n=m$.

Notes

No equivalent traditional C interface for this routine exists in the NAG Library.

The $n\times m$ matrix $B$ is post-multiplied by the $m\times p$ matrix $C$. If $opt=1$ the result is formed in the $n\times p$ matrix $A$. If $opt=2$, $m$ must equal $p$, and the result is written back to $B$. If $opt=3$, $n$ must equal $m$, and the result is written back to $C$.