## 56 Reputation

14 years, 259 days

## Extract a factor...

Maple 13

I would like to express a matrix in a neat(er) form.  For example, both matrices;

Matrix([[1/4, 1/2], [1/2, 1/4]]);

(1/2)*Matrix([[1/2, 1],[1, 1/2]]);

return the same thing.  I would like maple to print the latter with the factor 1/2 preceding the matrix for better clarity.  Is there a simple command that will do this?

Rob

## Rounding to zero...

Maple

I have an expression like; 0.7x + 5e-10y, which I would like to approximate to 0.7x.

Round won't work as it will also round the 0.7 down to zero.  I have tried using he Digits command, but it seems to only work half of the time.

Is there a simple command that can put a ceiling on a number like e-5, so that any number lower than that will not be returned?

Cheers;

Robert Ward

## algsubs & Operators...

Maple

Dear All

I am trying to substitute an expression that contains hermitian operators where the ordering is crucial.  I have tried algsubs and simplify-sidderels, but they both do nothing.

I am trying to substitute;

a + b*c*b = R

where all are defined as hermitian operators in the Physics package.

into an expression;

H = - a - b*c*b

but nothing happens...

However, when I substitute a = R - b*c*b, rather than getting H = -R, I get;

H = -R + c*b - b*c*b

## 10 minutes to evaluate an expression!...

Dear all

I am using the Phyiscs package in Maple, and I have an expression with 6 Dirac-Kets and symbols infront that conform to selection rules. e.g.

alpha*(a + b)|E1> + beta*(a - b)|E2> + beta*(3a + b)|E3>  + alpha*(a + 4b)|E4> + beta*(9a - 6b)|E5> + alpha*(3a + 6b)|E6>

However when I apply the command;

expand(Dagger(%).%)

## Forming a Matrix from Bra-kets...

Dear All

I am evaluating innerproducts between a cartesian basis set with an arbirtary operator, and the result is;

ans = <X|a[11]|X> + <X|a[12]|Y> + <X|a[13]|Z> +

<Y|a[21]|X> + <Y|a[22]|Y> + <Y|a[23]|Z> +

<Z|a[31]|X> + <Z|a[32|Y> + <Z|a[33]|Z>

I would like to put this into a matrix form (i.e. removing the bras and kets), so that

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