Preben Alsholm

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20 years, 244 days

MaplePrimes Activity


These are replies submitted by Preben Alsholm

@goli Here are the different commands.

restart;
eq:=x->y^(-1/5)*(y^2-(1+x)^3-(1+x)^4)=1;
Y:=x->fsolve(eq(x),y);
plot(Y,-10..10);
plots:-implicitplot(eq(x), x=-10..10,y=0..120,grid=[150,150]);
plot(fdiff(Y,[1],x),x=-2..2,caption="The derivative of y using fdiff on Y");
yp:=implicitdiff(eq(x),y,x);
plot(eval(yp,y='Y(x)'),x=-2..2,caption="The derivative of y using implicitdiff and Y");

@goli Here are the different commands.

restart;
eq:=x->y^(-1/5)*(y^2-(1+x)^3-(1+x)^4)=1;
Y:=x->fsolve(eq(x),y);
plot(Y,-10..10);
plots:-implicitplot(eq(x), x=-10..10,y=0..120,grid=[150,150]);
plot(fdiff(Y,[1],x),x=-2..2,caption="The derivative of y using fdiff on Y");
yp:=implicitdiff(eq(x),y,x);
plot(eval(yp,y='Y(x)'),x=-2..2,caption="The derivative of y using implicitdiff and Y");

After using combine you can use

convert(%,phaseamp,t);

After using combine you can use

convert(%,phaseamp,t);

My Maple 14 uses HeunG, no HG appears.

@GeorgesL In any case, it is not a bug. It is a decision that was made. What do you think 0^k should evaluate to, when k is unassigned?

@GeorgesL In any case, it is not a bug. It is a decision that was made. What do you think 0^k should evaluate to, when k is unassigned?

Good question.

I think the solution f = constant and g = 0 is unstable, so if your solution approaches such a solution the numerical solution may run into severe problems.

So you got work to do :-)

Good question.

I think the solution f = constant and g = 0 is unstable, so if your solution approaches such a solution the numerical solution may run into severe problems.

So you got work to do :-)

@soechristian Here is a simple example.

sys:={y=x^2-1,y=x};
res:=solve(sys,{x,y},explicit);

#This is just an example of the use of evaluating some expression at res[1] or res[2]:

expand(eval(x^2+y^2-1,res[1]));
expand(eval(x^2+y^2-1,res[2]));

#Now actually assigning
assign(res[1]);
x,y;

res[1] refers to the first result in the sequence res.

@soechristian Here is a simple example.

sys:={y=x^2-1,y=x};
res:=solve(sys,{x,y},explicit);

#This is just an example of the use of evaluating some expression at res[1] or res[2]:

expand(eval(x^2+y^2-1,res[1]));
expand(eval(x^2+y^2-1,res[2]));

#Now actually assigning
assign(res[1]);
x,y;

res[1] refers to the first result in the sequence res.

@hirnyk For some functions coords = polar makes the pictures look nice:

 

plots:-conformal(z,z=0..1+Pi*I,numxy=[20,100],grid=[10,25],coords=polar,scaling=constrained,caption="The z-plane"):

plots:-conformal(z,z=0..1+Pi*I,numxy=[20,100],grid=[10,25],coords=polar,scaling=constrained,caption="The z-plane")
plots:-conformal(sec(z),z=0..1+Pi*I,numxy=[20,100],grid=[10,25],coords=polar,scaling=constrained,caption="The w-plane"):

plots:-conformal(sec(z),z=0..1+Pi*I,numxy=[20,100],grid=[10,25],coords=polar,scaling=constrained,caption="The w-plane")
plots:-display(Array([%%,%]));

@hirnyk For some functions coords = polar makes the pictures look nice:

 

plots:-conformal(z,z=0..1+Pi*I,numxy=[20,100],grid=[10,25],coords=polar,scaling=constrained,caption="The z-plane"):

plots:-conformal(z,z=0..1+Pi*I,numxy=[20,100],grid=[10,25],coords=polar,scaling=constrained,caption="The z-plane")
plots:-conformal(sec(z),z=0..1+Pi*I,numxy=[20,100],grid=[10,25],coords=polar,scaling=constrained,caption="The w-plane"):

plots:-conformal(sec(z),z=0..1+Pi*I,numxy=[20,100],grid=[10,25],coords=polar,scaling=constrained,caption="The w-plane")
plots:-display(Array([%%,%]));

@Orion Is it going to help any to replace ``  with f (assuming that f doesn't evaluate to anything but its own name)? As in

eval(p2(u),``=f);

At least you only get a warning when doing

CodeGeneration:-Fortran(eval(p2(u),``=f));

You would have to remove f all over the place though. But that could be done in a text editor with Edit/replace.

@Orion Is it going to help any to replace ``  with f (assuming that f doesn't evaluate to anything but its own name)? As in

eval(p2(u),``=f);

At least you only get a warning when doing

CodeGeneration:-Fortran(eval(p2(u),``=f));

You would have to remove f all over the place though. But that could be done in a text editor with Edit/replace.

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