Alger

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11 years, 116 days

MaplePrimes Activity


These are replies submitted by Alger

@Axel Vogt 

Could you explane what is storage sparse Matrix ?

In Maple the explanation is in NAG/f11

  

A=(1,,,2,,,-1,,,-1,,,-3,,,-1,,,-4,,,3,,,2,,,2,,,4,,,1,,,1,,,-2,,,1)

  

IROW=(1,,,1,,,1,,,1,,,1,,,2,,,2,,,3,,,3,,,4,,,4,,,4,,,4,,,5,,,5)

  

ICOL=(1,,,2,,,3,,,4,,,5,,,2,,,5,,,1,,,5,,,1,,,3,,,4,,,5,,,1,,,5)

 

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)

@Axel Vogt 

If I understand and if you read this:

a Matrix might be represented in the arrays A, IROW and ICOL as

  

A=(1,,,2,,,-1,,,-1,,,-3,,,-1,,,-4,,,3,,,2,,,2,,,4,,,1,,,1,,,-2,,,1)

  

IROW=(1,,,1,,,1,,,1,,,1,,,2,,,2,,,3,,,3,,,4,,,4,,,4,,,4,,,5,,,5)

  

ICOL=(1,,,2,,,3,,,4,,,5,,,2,,,5,,,1,,,5,,,1,,,3,,,4,,,5,,,1,,,5).

This is what I said ?

@Axel Vogt 

If I understand and if you read this:

a Matrix might be represented in the arrays A, IROW and ICOL as

  

A=(1,,,2,,,-1,,,-1,,,-3,,,-1,,,-4,,,3,,,2,,,2,,,4,,,1,,,1,,,-2,,,1)

  

IROW=(1,,,1,,,1,,,1,,,1,,,2,,,2,,,3,,,3,,,4,,,4,,,4,,,4,,,5,,,5)

  

ICOL=(1,,,2,,,3,,,4,,,5,,,2,,,5,,,1,,,5,,,1,,,3,,,4,,,5,,,1,,,5).

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 ?

@tennisman03110 

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]));

 

@tennisman03110 

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]));

 

@hirnyk 

Yes it is simple

Thank you

@hirnyk 

Yes it is simple

Thank you

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

 

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

 

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

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

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}

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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