Child FFD deltas not calculated with the same point set as parent. about pygeo HOT 3 OPEN

@joanibal can you post the global design variable function you used in the child?

While writing the tutorial I wanted to understand why global variable funcs that use += operations work properly. When self.update() is called, the FFD coefficients are set back to their original (baseline) locations and then the global DVs are computed in order of their addition, then sectionlocal and local variables. So you don't accumulate changes across iterations via += operations.

On the other hand, child FFDs do some weird stuff that I don't totally understand, but I don't think it's doing the same reset. So if you used += or *= operations in your child global dv funcs, it could lead to some weird behavior. It may or may not be relevant to your debugging here

        if not self.isChild:
            self.FFD.coef = self.origFFDCoef.copy()
            self._setInitialValues()
        else:
            # Update all coef
            self.FFD._updateVolumeCoef()

            # Evaluate starting pointset
            Xstart = self.FFD.getAttachedPoints(ptSetName)

            if self.complex:
                # Now we have to propagate the complex part through Xstart
                tempCoef = self.FFD.coef.copy().astype('D')
                Xstart = Xstart.astype('D')
                imag_part = numpy.imag(tempCoef)
                imag_j = 1j

                dPtdCoef = self.FFD.embededVolumes[ptSetName].dPtdCoef
                if dPtdCoef is not None:
                    for ii in range(3):
                        Xstart[:, ii] += imag_j*dPtdCoef.dot(imag_part[:, ii])

from pygeo.

Here are the functions I used with child FFDs

def twist_flap(val, geo):
    geo.rot_z['flap_axis'].coef[:] = val[:] - 29.5


def translate_x_flap(val, geo):
    C = geo.extractCoef('flap_axis')
    C[:, 0] += val[:] + 0.15421028
    geo.restoreCoef(C, 'flap_axis')


def translate_y_flap(val, geo):
    C = geo.extractCoef('flap_axis')
    C[:, 1] += val[:] - 0.0816069
    geo.restoreCoef(C, 'flap_axis')


def twist_slat(val, geo):
    geo.rot_z['slat_axis'].coef[:] = val[:] + 29.0


def translate_x_slat(val, geo):
    C = geo.extractCoef('slat_axis')
    C[:, 0] += val[:] - .0911552
    geo.restoreCoef(C, 'slat_axis')


def translate_y_slat(val, geo):
    C = geo.extractCoef('slat_axis')
    C[:, 1] += val[:] - 0.0735696
    geo.restoreCoef(C, 'slat_axis')

from pygeo.

Yeah I can't say for certain that the weird behavior is caused by the per-iteration reset behavior of the coefficients referenced by C = geo.extractCoef('slat_axis') but it's possible.

from pygeo.