• #### User function in "using" expression

From layzarc@aol.com@21:1/5 to All on Wed Aug 28 12:01:04 2019
I'm trying to use gnuplot to solve a specific version of the problem

3d plot z(x,y) with x,ys subject to the constraint f(x,y)=0

The following works (the files are 0 contours captured by set table)

array n
file(i) = sprintf("coma%d.gpt",i)
splot for [i=1:|n|] file(i) using 1:2:(0):(0):(0):(1) with vectors

but if I also do:

phi(x,y) = (1+x)/(1+sqrt(1+(x*x-1)*y))
spher(n,x,y) = (f=phi(x,y),n2=n*n,((f-n)^2*(f-n2)*(1-y*f)-f^3)/(n2*(n-1)^3)) splot for [i=1:|n|] file(i) using 1:2:(0):(0):(0):(spher(n[i],\$1,\$2)) with vectors

I get the following message:

non-integer passed to boolean operator

What am I missing? I can provide the full file if needed.

Al

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• From layzarc@aol.com@21:1/5 to All on Wed Aug 28 13:09:57 2019
Karl,

Duh! I knew that but copied the expression from another software and forgot to make the changes. Advantage of having a second set of eyes.

Thanks,
Al

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• From Karl Ratzsch@21:1/5 to All on Wed Aug 28 22:01:23 2019
Am 28.08.2019 um 21:01 schrieb layzarc@aol.com:
I'm trying to use gnuplot to solve a specific version of the problem

3d plot z(x,y) with x,ys subject to the constraint f(x,y)=0

The following works (the files are 0 contours captured by set table)

array n
file(i) = sprintf("coma%d.gpt",i)
splot for [i=1:|n|] file(i) using 1:2:(0):(0):(0):(1) with vectors

but if I also do:

phi(x,y) = (1+x)/(1+sqrt(1+(x*x-1)*y))
spher(n,x,y) = (f=phi(x,y),n2=n*n,((f-n)^2*(f-n2)*(1-y*f)-f^3)/(n2*(n-1)^3)) splot for [i=1:|n|] file(i) using 1:2:(0):(0):(0):(spher(n[i],\$1,\$2)) with vectors

I get the following message:

non-integer passed to boolean operator

the exponential operator in gnuplot is ** , not ^

| |A| cardinality of array A

thanks. ;)

Karl

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• From Karl Ratzsch@21:1/5 to All on Wed Aug 28 21:53:06 2019
Am 28.08.2019 um 21:01 schrieb layzarc@aol.com:
I'm trying to use gnuplot to solve a specific version of the problem

3d plot z(x,y) with x,ys subject to the constraint f(x,y)=0

The following works (the files are 0 contours captured by set table)

array n
file(i) = sprintf("coma%d.gpt",i)
splot for [i=1:|n|] file(i) using 1:2:(0):(0):(0):(1) with vectors

but if I also do:

phi(x,y) = (1+x)/(1+sqrt(1+(x*x-1)*y))
spher(n,x,y) = (f=phi(x,y),n2=n*n,((f-n)^2*(f-n2)*(1-y*f)-f^3)/(n2*(n-1)^3)) splot for [i=1:|n|] file(i) using 1:2:(0):(0):(0):(spher(n[i],\$1,\$2)) with vectors

I get the following message:

non-integer passed to boolean operator

What am I missing? I can provide the full file if needed.

Al

gnuplot uses

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