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|int||construct_tracegeom (tracegeom *tg, char *fin, char *fout, float tol, FILE *stream)|
|Trace geometry constructor. |
|int||init_tracegeom (tracegeom *tg, RPNT og, IPNT n, RPNT d, RPNT o, IPNT axord, int order, float dt, int ndim, int usernt, float usert0, int initbuf, FILE *stream)|
|Initialization for trace geometry object. |
|void||destroy_tracegeom (tracegeom *tg)|
|destructor: frees all dynamically allocated memory, closes files. |
|void||setnull_tracegeom (tracegeom *tg)|
|default initialization (as distinct from construction)- sets tracelength to zero, all other internals to zero or other sensible default values. |
|void||fprint_tracegeom (tracegeom const *tg, FILE *fp)|
|diagnostic output to stream (fp). |
|void||print_tracegeom (tracegeom const *tg)|
|diagnostic output to stdout. |
|void||sampletraces (tracegeom *tg, int order, int load, int it, IPNT allocstrides, IPNT allocorigs, IPNT strides, IPNT origs, ireal *field, ireal mult)|
|Sampling function. |
|int||writetraces (tracegeom const *tg, RPNT d, RPNT og, FILE *stream)|
|Trace output. |
|void||calc_group (int *first, int *last, int nrec)|
|int construct_tracegeom||(||tracegeom *||tg,|
Trace geometry constructor.
Calling this function
|[out]||tg||- (tracegeom *) trace geometry object to be constructed|
|[in]||fin||- (char *) name of header (input) file.|
|[in]||fout||- (char *) name of data (output) file|
|[in]||tol||- (float) tolerance for distinguishing source positions with l-infty norm; should be computed in calling unit as fraction of maximum space step of grid to be sampled, possibly using cpp macro SRC_TOL defined in the header file.|
|[in]||stream||- (FILE *) output stream for diagnostic information.|
|int init_tracegeom||(||tracegeom *||tg,|
Initialization for trace geometry object.
Takes spatial geometry and start and end time from input file. Time sample rate specified externally (arg dt), determines buffer allocation. Time unit is ms. It is ASSUMED that any common spatial data (eg. scalel, scalco) is uniform, and may be read from any trace.
The data to be sampled repeatedly to form traces are assumed to functions on a uniform rectangular grid. The construction of samples differentiates between a LOCAL grid, meaning the grid on which the data to be sampled are being updated by the process, and a GLOBAL grid, of which the LOCAL grid is a subgrid. Index tuples are defined by the GLOBAL grid. The sampling function (below) is supplied with the index tuple of the LOCAL grid origin, which enables conversion from global indices to local offset.
This function does several tasks, using the tracegeom struct to record its results:
The routine may be called several times to initialize any number of time series on the same internal time grid. This internal (stepping) time grid is fixed by the requirement tha (1) the step be given by the input argument dt, and (2) t=0 is a sample point.
|[out]||tg||(tracegeom *) trace geometry object to be initialized|
|[in]||og||(RPNT) coordinates of GLOBAL grid origin (grid point with all indices = 0) relative to physical coordinate system. The physical coordinate system refers to the physical domain, and is the coordinate system with respect to which the source and receiver coordinates are defined. These numbers (lengths, not indices!) give the coordinates of the global computational grid origin in the physical system.|
|[in]||n||(IPNT) number of samples on each axis for the LOCAL subgrid in which traces are to be sampled.|
|[in]||o||(RPNT) coordinates of LOCAL subgrid origin.|
|[in]||d||(RPNT) spatial steps (common to GLOBAL grid and LOCAL subgrid)|
|[in]||dt||(float) time step in ms. input argument, NOT read from file - computed by the simulator, actual time step between time levels of simulation. Recorded in tracegeom object as tg->dt.|
|[in]||ndim||(int) dimension of GLOBAL and LOCAL grids.|
|[in]||usernt,usert0||(int, float) optional specification of number output samples and time of first output sample. If set (i.e. usernt > 0), then |
|[in]||initbuf||(int) flag for data initiation. If set, data traces are read and transferred to the internal simulation (tg->dt,tg->nt,tg->t0) grid by adjoint cubic interpolation (see Cubic Spline Interpolation and Adjoint Interpolation). To avoid temp storage, this option implemented by another pass through file.|
|[in]||axord||(int) The axord argument codes axis order as follows: |
|[in]||order||(int) interpolation order for non-grid source and receiver positions - current legal values are 0 and 1|
|[in]||stream||(FILE *) verbose output stream|
|void destroy_tracegeom||(||tracegeom *||tg||)|
destructor: frees all dynamically allocated memory, closes files.
Should be called as part of "default constructor"
|void setnull_tracegeom||(||tracegeom *||tg||)|
default initialization (as distinct from construction)- sets tracelength to zero, all other internals to zero or other sensible default values.
Leaves files open, does not reset whole-data-set dependent quantities. Should be called to initialized structure for new record.
|void fprint_tracegeom||(||tracegeom const *||tg,|
diagnostic output to stream (fp).
|void print_tracegeom||(||tracegeom const *||tg||)|
diagnostic output to stdout.
|void sampletraces||(||tracegeom *||tg,|
To be called at every time step. Index arrays defined relative to global grid. Requires both local (to each process) strides and origins of allocated grid, to compute offset into array to be sampled, and strides and origins of computational grid (array of points to be updated by each processor. Only those summands in interpolation formulas computed corresponding to these computational grid points - since computational grids do not overlap, each interpolation term is computed by at most one processor. If no processor computes a term, then point contributing belongs to no computational grid, i.e. lies on Dirichlet for the corresponding field. TODO: this idea certainly works for the pressure, but needs to be checked for sampling velocity in the near-boundary layer.
Version 1.5 addendum: the final argument is a scale factor, applied to every sample. For load (adjoint to save), an additional factor of cell volume ratio is applied - that is, time step / volume of spatial cell.
|[out]||tg||(tracegeom) trace geometry - output for save, input for load. defines sampling of grid, samples saved to buffer tg.buf in save mode, loaded from tg.buf in load mode.|
|[in]||order||(int) order of interpolation rule.- either trilinear (order=1) or nearest neighbor (order=0 are supported;|
|[in]||load||(int) if set, transfer data from traces to grid by adj interp; else, transfer data from grid to traces by interp|
|[in]||it||(int) time step index for sampling - function is no-op if it < 0 or it > tg.nt-1;|
|[in]||allocstrides||(IPNT) number of samples on each local ALLOCATED grid axis;|
|[in]||allocorigs||(IPNT) index tuple of local ALLOCATED grid origin relative to global grid;|
|[in]||strides||(IPNT) number of samples on each local COMPUTATIONAL grid axis (updated points);|
|[in]||origs||(IPNT) index tuple of local COMPUTATIONAL grid origin relative to global grid;|
|[in]||field||(float *) (input for save, output for load) buffer containing grid data to be sampled.|
|[in]||mult||(ireal) scale factor for samples - for load (adjoint of save), scaled by ratio of cell volumes|
Sets up internal segy for writing, by transferring ntout, dtout, scalel, scalco, etc. to header fields. writes out traces. Uses axis steps and origin coordinates combined with index and relative coordinate data for source and receiver locations to compute trace headers. On return, fname will be SU file in working directory.
|[in]||tg||(tracegeom) header and trace data to be sampled;|
|[in]||d||(RPNT) axis steps in grid;|
|[in]||og||(RPNT) coordinate tuple for origin of GLOBAL grid;|
|[in]||stream||(FILE *) verbose output stream|
|void calc_group||(||int *||first,|