* * index_to_grid.F * * Jonathan Callahan * Feb 25th 2002 * * This function reads in tuples (i,j,val) which correspond * to the FORTRAN indices of the value. Some sites use this * method to compress data for gridded fields. * * The fourth argument contains the destination grid. * * The tuples are assumed to already be defined on an abstract * X and real Z and T axes. The examples I have seen so far * are model output at a single level and multiple timesteps. * The tuple output only corresponds to the X and Y axes and * is used instead of assigning bad flags or masks. * * Note that the FORTRAN indices I and J DO NOT correspond * to the Ferret indices I and J. The following interpretation * is made: * * FORTRAN I = row number = FERRET J = latitude (perhaps oriented N->S) * FORTRAN J = col number = FERRET I = longitude * * In this subroutine we provide information about * the function. The user configurable information * consists of the following: * * descr Text description of the function * * num_args Required number of arguments * * axis_inheritance Type of axis for the result * ( CUSTOM, IMPLIED_BY_ARGS, NORMAL, ABSTRACT ) * CUSTOM - user defined axis * IMPLIED_BY_ARGS - same axis as the incoming argument * NORMAL - the result is normal to this axis * ABSTRACT - an axis which only has index values * * piecemeal_ok For memory optimization: * axes where calculation may be performed piecemeal * ( YES, NO ) * * * For each argument we provide the following information: * * name Text name for an argument * * unit Text units for an argument * * desc Text description of an argument * * axis_influence Are this argument's axes the same as the result grid? * ( YES, NO ) * * axis_extend How much does Ferret need to extend arg limits relative to result * SUBROUTINE index_to_grid_init(id) INCLUDE 'ferret_cmn/EF_Util.cmn' INTEGER id, arg CALL ef_version_test(ef_version) * ********************************************************************** * USER CONFIGURABLE PORTION | * | * V CALL ef_set_desc(id, . 'puts (I,J,VAL) tuples on grid of D' ) CALL ef_set_num_args(id, 4) CALL ef_set_axis_inheritance(id, IMPLIED_BY_ARGS, . IMPLIED_BY_ARGS, IMPLIED_BY_ARGS, IMPLIED_BY_ARGS) CALL ef_set_piecemeal_ok(id, NO, NO, NO, NO) arg = 1 CALL ef_set_arg_name(id, arg, 'I') CALL ef_set_arg_desc(id, arg, 'Fortran I index (row) of VAL ') CALL ef_set_axis_influence(id, arg, NO, NO, NO, NO) arg = 2 CALL ef_set_arg_name(id, arg, 'J') CALL ef_set_arg_desc(id, arg, 'Fortran J index (column) of VAL') CALL ef_set_axis_influence(id, arg, NO, NO, NO, NO) arg = 3 CALL ef_set_arg_name(id, arg, 'VAL') CALL ef_set_arg_desc(id, arg, 'Value at grid cell [I,J]') CALL ef_set_axis_influence(id, arg, NO, NO, YES, YES) arg = 4 CALL ef_set_arg_name(id, arg, 'D') CALL ef_set_arg_desc(id, arg, 'destination grid taken from D') CALL ef_set_axis_influence(id, arg, YES, YES, NO, NO) * ^ * | * USER CONFIGURABLE PORTION | * ********************************************************************** RETURN END * * In this subroutine we compute the result * SUBROUTINE index_to_grid_compute(id, arg_1, arg_2, arg_3, arg_4, . result) INCLUDE 'ferret_cmn/EF_Util.cmn' INCLUDE 'ferret_cmn/EF_mem_subsc.cmn' INTEGER id REAL bad_flag(1:EF_MAX_ARGS), bad_flag_result REAL arg_1(mem1lox:mem1hix, mem1loy:mem1hiy, . mem1loz:mem1hiz, mem1lot:mem1hit) REAL arg_2(mem2lox:mem2hix, mem2loy:mem2hiy, . mem2loz:mem2hiz, mem2lot:mem2hit) REAL arg_3(mem3lox:mem3hix, mem3loy:mem3hiy, . mem3loz:mem3hiz, mem3lot:mem3hit) REAL arg_4(mem4lox:mem4hix, mem4loy:mem4hiy, . mem4loz:mem4hiz, mem4lot:mem4hit) REAL result(memreslox:memreshix, memresloy:memreshiy, . memresloz:memreshiz, memreslot:memreshit) * After initialization, the 'res_' arrays contain indexing information * for the result axes. The 'arg_' arrays will contain the indexing * information for each variable's axes. INTEGER res_lo_ss(4), res_hi_ss(4), res_incr(4) INTEGER arg_lo_ss(4,1:EF_MAX_ARGS), arg_hi_ss(4,1:EF_MAX_ARGS), . arg_incr(4,1:EF_MAX_ARGS) * ********************************************************************** * USER CONFIGURABLE PORTION | * | * V INTEGER i,j,k,l INTEGER i3,j3,k3,l3 INTEGER index_i,index_j CALL ef_get_res_subscripts(id, res_lo_ss, res_hi_ss, res_incr) CALL ef_get_arg_subscripts(id, arg_lo_ss, arg_hi_ss, arg_incr) CALL ef_get_bad_flags(id, bad_flag, bad_flag_result) * First -- populate the result with bad flags. DO 400 i=res_lo_ss(X_AXIS), res_hi_ss(X_AXIS) DO 300 j=res_lo_ss(Y_AXIS), res_hi_ss(Y_AXIS) DO 200 k=res_lo_ss(Z_AXIS), res_hi_ss(Z_AXIS) DO 100 l=res_lo_ss(T_AXIS), res_hi_ss(T_AXIS) result(i,j,k,l) = bad_flag_result 100 CONTINUE 200 CONTINUE 300 CONTINUE 400 CONTINUE * Second -- Loop over the K and L axes. * Put the values where they belong. * * Assumption: I,J,VAL are on the same grid. * Assumption: I is the row # and is associated with a latitude * Assumption: J is the col # and is associated with a longitude i = res_lo_ss(X_AXIS) j = res_lo_ss(Y_AXIS) k = res_lo_ss(Z_AXIS) l = res_lo_ss(T_AXIS) * Note: there should not be a Y axis on argument 3 j3 = arg_lo_ss(Y_AXIS,ARG3) l3 = arg_lo_ss(T_AXIS,ARG3) DO 700 l=res_lo_ss(T_AXIS), res_hi_ss(T_AXIS) k3 = arg_lo_ss(Z_AXIS,ARG3) DO 600 k=res_lo_ss(Z_AXIS), res_hi_ss(Z_AXIS) DO 500 i3=arg_lo_ss(X_AXIS,ARG3), arg_hi_ss(X_AXIS,ARG3) index_i = i - 1 + arg_2(i3,j3,k3,l3) index_j = j - 1 + arg_1(i3,j3,k3,l3) result(index_i,index_j,k,l) = arg_3(i3,j3,k3,l3) 500 CONTINUE k3 = k3 + arg_incr(Z_AXIS,ARG3) 600 CONTINUE l3 = l3 + arg_incr(T_AXIS,ARG3) 700 CONTINUE * ^ * | * USER CONFIGURABLE PORTION | * ********************************************************************** RETURN END