Obtain a quadratic approximation to a 2D Mapping astQuadApprox
"
lbnd"
and "
ubnd"
. The Mapping must have 2 inputs, but
may have any number of outputs. The i’
th Mapping output is modelled as a quadratic
function of the 2 inputs (x,y):
output_i = a_i_0 a_i_1x a_i_2y a_i_3xy a_i_4xx a_i_5yy
The "
fit"
array is returned holding the values of the co-efficients
a_0_0, a_0_1, etc.
’
s Nin attribute. This box should specify the region over which the fit is to
be performed. "
lbnd[0]"
and
the last is at "
ubnd[0]"
. If a value less than three is supplied a value of three
will be used. "
lbnd[1]"
and the last is at "
ubnd[1]"
. If a value
less than three is supplied a value of three will be used. "
6Nout"
, elements. The first 6 elements hold the fit to the first Mapping output. The next 6
elements hold the fit to the second Mapping output, etc. So if the Mapping has 2
inputs and 2 outputs the quadratic approximation to the forward transformation
is:
X_out = fit[0] fit[1]X_in fit[2]Y_in fit[3]X_inY_in fit[4]X_inX_in fit[5]Y_inY_in Y_out = fit[6] fit[7]X_in fit[8]Y_in fit[9]X_inY_in fit[10]X_inX_in fit[11]Y_inY_in
This function fits the Mapping’
s forward transformation. To fit the inverse
transformation, the Mapping should be inverted using astInvert before invoking this
function.
A value of zero will be returned if this function is invoked with the global error status set, or if it should fail for any reason.