get the value of the function, and its first & second derivative
Reimplemented from C2Function. Definition at line 1177 of file C2Functions.py. 01177 : 01178 if self.xNonLin or self.yNonLin: #skip this if this is a completely untransformed spline 01179 y0, yp0, ypp0=_splint(self.X, self.F, self.y2, self.fXin(x), derivs=True) 01180 y=self.fYout(y0) 01181 fpi=1.0/self.fYinP(y) 01182 gp=self.fXinP(x) 01183 01184 # from Mathematica Dt[InverseFunction[f][g[y[x]]], x] 01185 yprime=gp*yp0*fpi # the real derivative of the inverse transformed output 01186 fpp=self.fYinPP(y) 01187 gpp=self.fXinPP(x) 01188 #also from Mathematica Dt[InverseFunction[f][g[y[x]]], {x,2}] 01189 yprimeprime=(gp*gp*ypp0 + yp0*gpp - gp*gp*yp0*yp0*fpp*fpi*fpi)*fpi 01190 return native(y, yprime, yprimeprime) 01191 else: 01192 return _splint(self.X, self.F, self.y2, x, derivs=True)
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