UCVM 13.9.0 Developer Guide

Overview

This guide is intended for users looking to modify the UCVM source code, register new models with UCVM, or integrate UCVM into their own projects. Most common functionality, including mesh generation and getting material properties from models, is described in the main user guide.

Released on September 8th, 2013, UCVM 13.9.0 represents the second major release of the Unified Community Velocity Model (UCVM) framework. While at its core, UCVM is a collection of software utilities that are designed to make interacting with velocity models easier, it also includes a powerful API for interacting with or registering new velocity models. UCVM's API makes it very easy to integrate into software projects.

Query a Velocity Model in Your Code

C

Calling UCVM from C code is relatively trivial. Minimally, you need the UCVM library as well as "ucvm.h".

Using UCVM involves three fundamental steps: 1) Initializing UCVM through the ucvm_init function, 2) adding appropriate models through the ucvm_add_model function, and 3) retrieving material properties through the ucvm_query function. These functions are shown in the example below.

Example.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <sys/time.h>
#include "ucvm.h"

int main(int argc, char **argv)
{
  int nn = 1;
  ucvm_point_t pnts;
  ucvm_data_t data;
  char cmb_label[UCVM_MAX_LABEL_LEN];

  printf("Init\n");
  if (ucvm_init("../conf/test/ucvm.conf") != UCVM_CODE_SUCCESS) {
    fprintf(stderr, "Init failed\n");
    return(1);
  }

  printf("Query Mode\n");
  if (ucvm_setparam(UCVM_PARAM_QUERY_MODE,
                    UCVM_COORD_GEO_DEPTH) != UCVM_CODE_SUCCESS) {
    fprintf(stderr, "Failed to set z mode\n");
    return(1);
  }

  printf("Add Crustal Model 1D\n");
  if (ucvm_add_model(UCVM_MODEL_1D) != UCVM_CODE_SUCCESS) {
    fprintf(stderr, "Retrieval of 1D failed\n");
    return(1);
  }

  printf("Add GTL Model Ely\n");
  if (ucvm_add_model(UCVM_MODEL_ELYGTL) != UCVM_CODE_SUCCESS) {
    fprintf(stderr, "Retrieval of Ely GTL failed\n");
    return(1);
  }

  /* Change GTL interpolation function from default (linear)
     to Ely interpolation */
  if (ucvm_assoc_ifunc(UCVM_MODEL_ELYGTL,
                       UCVM_IFUNC_ELY) != UCVM_CODE_SUCCESS) {
    fprintf(stderr,
            "Failed to associate interpolation function with Ely GTL\n");
    return(1);
  }

  /* Change interpolation z range from 0,0 to 0,350 */
  if (ucvm_setparam(UCVM_PARAM_IFUNC_ZRANGE, 0.0,
                    350.0) != UCVM_CODE_SUCCESS) {
    fprintf(stderr, "Failed to set interpolation range\n");
    return(1);
  }

  printf("Create point\n");
  pnts.coord[0] = -118.0;
  pnts.coord[1] = 34.0;
  pnts.coord[2] = 2000.0;

  printf("Query Model\n");
  if (ucvm_query(nn, &pnts, &data) != UCVM_CODE_SUCCESS) {
    fprintf(stderr, "Query UCVM failed\n");
    return(1);
  }

  /* Get cmb data label */
  ucvm_ifunc_label(data.cmb.source,
                   cmb_label, UCVM_MAX_LABEL_LEN);

  printf("Results:\n");
  printf("\tsource=%s, vp=%lf, vs=%lf, rho=%lf\n",
         cmb_label, data.cmb.vp, data.cmb.vs, data.cmb.rho);

  return(0);
}

Fortran

Calling UCVM using Fortran is a relatively trivial procedure. After you have installed UCVM as per this user guide, you must include the UCVM library, the Proj.4 library, the e-tree library, as well as any velocity model libraries that you have compiled into UCVM. For CVM-H, please note that there are actually two libraries required: lvxapi and lgeo. Because the default convention for calling C programs from Fortran automatically appends an underscore to the end of the function name, you must turn that off via a flag called "fno-underscoring". This will make the Fortran compiler try and find foo() instead of foo_().
As an example, suppose we have a Fortran file, example.f, that calls UCVM. We have compiled UCVM with CVM-S and CVM-H. The code to compile example.f would be as follows:

gfortran example.f -o ./example -L/path/to/ucvm-13.9.0/lib -L./path/to/ucvm-13.9.0/model/cvms4/lib -L/path/to/ucvm-13.9.0/model/cvmh1191/lib -L/path/to/ucvm-13.9.0/lib/proj-4/lib -L/path/to/ucvm-13.9.0/lib/euclid3/libsrc -lucvm -lcvms -lvxapi -lgeo -lproj -letree -fno-underscoring

The basic structure of how to call UCVM within Fortran is outlined in the example below.

Example.f

                program example
         
        c       UCVM Configuration Location
                CHARACTER(LEN=80) ucvmconf
        c       Model Name
                CHARACTER(LEN=4) model 
        c       Number of points we're passing to ucvm_query
                INTEGER pts      
         
        c       The UCVM point data structure. 
        c       coord(1) is longitude
        c       coord(2) is latitutde
        c       coord(3) is depth
                TYPE :: ucvm_point_t
                       REAL*8 coord(3)
                END TYPE ucvm_point_t
         
        c       Generic property structure
        c       Source is where it comes from
        c       vp is P-wave velocity in m/s
        c       vs is S-wave velocity in m/s
        c       rho is density in kg/m^3
                TYPE :: ucvm_prop_t
                        INTEGER source
                        REAL*8 vp
                        REAL*8 vs
                        REAL*8 rho
                END TYPE ucvm_prop_t
         
        c       Returned data structure
                TYPE :: ucvm_data_t
                        REAL*8 surf
                        REAL*8 vs30
                        REAL*8 depth
                        INTEGER domain
                        REAL*8 shift_cr
                        REAL*8 shift_gtl
                        type(ucvm_prop_t) crust
                        type(ucvm_prop_t) gtl
                        type(ucvm_prop_t) cmb
                END TYPE ucvm_data_t
         
        c       For our example we'll query five points
                type(ucvm_point_t) point(5)
        c       And we'll get back five sets of material properties
                type(ucvm_data_t) returnData(5)
         
        c       Number of points is 5.
                pts = 5
         
        c       We'll start at -118, 34 at 0 depth and go down by 1000m
        c       each step
                do 10 i = 1, 5
                        point(i)%coord(1) = -118
                        point(i)%coord(2) = 34
                        point(i)%coord(3) = (i - 1) * 1000
        10      continue
         
        c       Where is our configuration file?
                ucvmconf = "/home/scec-01/davidgil/ucvm.conf" // CHAR(0)
         
        c       What model are we querying?
                model = "cvms"
         
        c       Initialize UCVM
                call ucvm_init(ucvmconf)
         
        c       Add the model to UCVM
                call ucvm_add_model(model)
         
        c       Query the model. Note that the number of points is passed
        c       by value, not reference.
                call ucvm_query(%VAL(pts), point, returnData)
         
                print *, model, " results for lon -118, lat 34"
         
        c       Print out the results.
                do 20 i = 1, 5
                        print *, "Depth ", (i - 1) * 1000
                        print *, "Vs ", returnData(i)%crust%vs 
                        print *, "Vp ", returnData(i)%crust%vp 
                        print *, "Rho ", returnData(i)%crust%rho
        20      continue
         
        c       Close UCVM now that we've queried the points 
                call ucvm_finalize()
         
                end

GCC Fortran 4.3+ is required for this example to work.