Royal Belgian Institute for Aeronomy¶

uf427 - interpolating a value of B¶

subroutine uf427(fbm, bi, ai, ifail)¶

Parameters:

fbm [real8,in] :: Magnetic field intensity value to be interpolated.
bi [real8,out] :: Magnetic field intensity at the interpolated location.
ai [real8,out] :: Altitude at the interpolated location.
ifail [integer4,out] :: error flag (see Diagnostics)

Description¶

The subroutine uf427() interpolates a magnetic field intensity (fbm) along a field line. To be used, the common block uc170 has to include at least two points and the last Runge-Kutta step had to overreach the magnetic intensity fbm. The subroutine uf427() combines linear interpolations and Runge-Kutta steps to determine the correct location of the magnetic intensity fbm.

When the subroutine succeeds, the arguments bi and ai are set to the magnetic field intensity and altitude at the interpolated location, respectively. The index of the common block uc170 corresponding to the interpolated location is stored in the argument ifail.

Note

The subroutine takes into account the step size limit stplst defined in the common block uc190.

History¶

From version 1.13 to version 2.00, the subroutine code has been correct for an error which caused an undue error with diagnostic -42701.

Diagnostics¶

-42701, magnetic field intensity is constant

-42702, too many iterations

-42703, -42704, problem with the Runge Kutta step

> 0, the index in uc170 corresponding to the interpolated location

Common Blocks¶

uc160 - general constants

uc170 - temporary magnetic field line

uc190 - control parameters, set 1

Dependencies¶

Called by¶

uf422 - follow a field line until a boundary condition is reached

Calls¶

uf423 - Runge Kutta step

Reported Bugs¶

None

Examples¶