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(v) Setting patchwise coefficients and values

This section deals with how to re-set in GROUND the coefficient and value data first set in the SATELLITE. It is not concerned with how to set the PATCH-wise arrays of coefficients and values which are set in group 13 of GROUND when the third and fourth arguments of COVAL are GRND.

It would be reasonable to expect that COefficients and VALues could be set by use of a SETCOV subroutine. This, however, does not exist; so whoever wishes to set the COefficient and VALue of a PATCH should proceed as follows:

First, an extra common block must be added to the subroutine, namely:

Secondly, either GETCOV or GETSOR should be called. It does not matter which, because they both compute values of the index I0PHI. Thirdly, the COefficient and/or VALue should be set to the desired magnitude by one or both of the following statements:

F(I0PHI+2)=desired magnitude of COefficient
F(I0PHI+3)=desired magnitude of VALue

When should this be done? The answer depends on circumstances. Often, what the user wishes to do is to change the COefficients or VALues as time proceeds; in this case, Section 1 of group 19 is an appropriate location. Alternatively, the user may be wishing to incorporate a change to the COefficient and/or VALue which corresponds to a non-linear relationship between the source and the variable VALue. In that case, the user may wish to update COefficient and VALue in the course of iteration so as to represent some non-linear relationship. For this purpose, group 19 Section 4 would be an appropriate place for inserting the coding sequence.