## 499 Reputation

11 years, 116 days

## What is sparse Matrix ?...

Could you explane what is storage sparse Matrix ?

In Maple the explanation is in NAG/f11

In Matlab:

For example, this dissects and then reassembles a sparse matrix:

[i,j,s] = find(S);
[m,n] = size(S);
S = sparse(i,j,s,m,n);

S,i,j are vectors (arrays)

## NAG/f11 in help...

If I understand and if you read this:

a Matrix might be represented in the arrays ,  and  as

 .

This is what I said ?

## NAG/f11 in help...

If I understand and if you read this:

a Matrix might be represented in the arrays ,  and  as

 .

This is what I said ?

## Yes work in Maple 12 and not in Maple 14...

Yes work in Maple 12 and not in Maple 14 ?

## Yes work in Maple 12 and not in Maple 14...

Yes work in Maple 12 and not in Maple 14 ?

## One method...

When you want to introduce for some nodes

T[i]:=0 (or T0) for some nodes i for example:

In your Matrix A and vector B, you introduce this:

A[i,i]:=A[i,i]+value;

B[i]:=value*0 (or T0);

Generally value:=1E15*max(abs(A[i,j]));

## One method...

When you want to introduce for some nodes

T[i]:=0 (or T0) for some nodes i for example:

In your Matrix A and vector B, you introduce this:

A[i,i]:=A[i,i]+value;

B[i]:=value*0 (or T0);

Generally value:=1E15*max(abs(A[i,j]));

Yes it is simple

Thank you

Yes it is simple

Thank you

## Symbolically ?...

with(VectorCalculus):

int( x*y, [x,y] = Triangle( <0,0>, <1,0>, <0,1> ) );

This command give a value.

I want to do a calculation symbolically like this:

with(VectorCalculus):

int( x*y, [x,y] = Triangle( <x1,y1>, <x2,y2>, <x3,y3> ) );

Is it possible ?

I know that

int( x, [x,y] = Triangle( <x1,y1>, <x2,y2>, <x3,y3> ) ); is equal to xg*Se where xg=(1/3)(x1+x2+x3) and Se the area of the triangle

Thanks

## Symbolically ?...

with(VectorCalculus):

int( x*y, [x,y] = Triangle( <0,0>, <1,0>, <0,1> ) );

This command give a value.

I want to do a calculation symbolically like this:

with(VectorCalculus):

int( x*y, [x,y] = Triangle( <x1,y1>, <x2,y2>, <x3,y3> ) );

Is it possible ?

I know that

int( x, [x,y] = Triangle( <x1,y1>, <x2,y2>, <x3,y3> ) ); is equal to xg*Se where xg=(1/3)(x1+x2+x3) and Se the area of the triangle

Thanks

## Thanks, that is what I want...

Yes you are right and more simple to simplify the functions and piecewise functions. But, I use those functions for other thinks and I think I'm not wrong in my functions. Why the error ?

In my worksheet which I posted, I have only three lines but in your answer we have more and we must use command like add, subs, value, eval.

Thanks again

## Thanks, that is what I want...

Yes you are right and more simple to simplify the functions and piecewise functions. But, I use those functions for other thinks and I think I'm not wrong in my functions. Why the error ?

In my worksheet which I posted, I have only three lines but in your answer we have more and we must use command like add, subs, value, eval.

Thanks again

## range ?...

When I execut your command below in Maple 14

S2:=fsolve({x=0,y=0,z=0,w=0},{a=1.0,b=1.0,c=1.0,d=1.0},{a=0..7,b=0..7,c=0..7,d=0..7},avoid=S1);

fsolve don't give a result

When I change the range for a=0..8, I have this result

S1:=fsolve({x=0,y=0,z=0,w=0},{a=1.0,b=1.0,c=1.0,d=1.0},{a=0..8,b=0..7,c=0..7,d=0..7},avoid={a = 2.663589361, b = .2708302726, c = 4.120270119, d = .4866603365});

S1 := {a = 3.619595946, b = 1.405424580, c = 6.769845644, d = 4.120270119}

## range ?...

When I execut your command below in Maple 14

S2:=fsolve({x=0,y=0,z=0,w=0},{a=1.0,b=1.0,c=1.0,d=1.0},{a=0..7,b=0..7,c=0..7,d=0..7},avoid=S1);

fsolve don't give a result

When I change the range for a=0..8, I have this result

S1:=fsolve({x=0,y=0,z=0,w=0},{a=1.0,b=1.0,c=1.0,d=1.0},{a=0..8,b=0..7,c=0..7,d=0..7},avoid={a = 2.663589361, b = .2708302726, c = 4.120270119, d = .4866603365});

S1 := {a = 3.619595946, b = 1.405424580, c = 6.769845644, d = 4.120270119}

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