You are trying to assign a value to the result of std::real which is a rvalue . That makes as much sense as writing 5.0f = std::real(output_seq[y]) + (V2[x] * cosineA); So you probably want to do this instead output_seq[y] = std::real(output_seq[y]) + (V2[x] * cosineA); ...

The best solution I could come up with was to use cylindrical billboarding for depth calculations and spherical for the quad's actual position. This allows you to use spherical billboarding while ensuring the quad's depth remains constant. For reference here are the billboarding ModelView Matrixes. [x]: implies the value is...

python,numpy,scipy,ipython,quad

Reread the docstring for dblquad. The fourth and fifth arguments must be callable (i.e. functions). You have passed in 0 and np.inf. The functions are the lower and upper bounds of the inner integral. There is an example in the tutorial....

rotation,opengl-es-2.0,transformation,quad

OpenGL ES 2.0 does not really have a concept of angles. We don't see this in the code you posted, but somebody builds a rotation matrix from the angle, which most likely ends up in the mRotationMatrix variable based on the code you show. Almost any transformation matrix you use...

fortran,precision,gfortran,quad

In general, things like "dabs" were from the days before type-generic intrinsics. In particular, there is no corresponding "qabs/absq" or whatever you might want to call it, but rather only the type-generic "abs" which is then resolved to the correct library symbol at compile time. Secondly, your choice of "abs"...

You can use an anonymous function defined only in x to evaluate F(x,y) when y is known Q = quad(@(x) F(x,y), 0, 2) ...

python,python-3.x,scipy,integration,quad

The reason here is that your function is only very strongly peaked in a very small region of your integration region and is effectively zero everywhere else, quad never finds this peak and thus only see's the integrand being zero. Since in this case you know where the peaks are,...