build_poly

Synopsis

build_poly POLY_FILE [options]

Description

The build_poly tool constructs a composite polytrope, and writes it to a file in the POLY format.

Options

-h, --help: Print a summary of options.

-n, --n_poly=N_POLY[,N_POLY...]: Polytropic indices \(\npoly\) (either a single value, or a comma-separated list of values, one for each region).

-G, --Gamma_1=GAMMA_1: Adiabatic index \(\Gamma_{1}\).

-z, --z_b=Z_B[,Z_B...]: Polytropic coordinate of region boundaries.

-D, --Delta_b=DELTA_B[,DELTA_B...]: Logarithmic density jumps at region boundaries.

--theta_s=THETA_S: Surface polytropic variable value.

-d, --dz=DZ: Grid spacing in polytropic coordinate.

-t, --toler=TOLER: Tolerance of Lane-Emden equation solver.

Examples

To build a simple (complete) polytrope with \(\npoly=3\), run build_poly as follows:

$ $GYRE_DIR/bin/build_poly --n_poly=3 --dz=0.01 poly.simple.h5

This model, written to the file poly.simple.h5, is visualized in the figure below.

Plot showing the structure of the simple polytrope model — Fig. 12 Plot of the Lane-Emden solution variable \(\theta\), density \(\rho\), pressure \(P\) and interior mass \(M_{r}\) as a function of radial coordinate, for the simple polytrope. (`Source`)

To build a composite polytrope, comprising two regions (inner \(\npoly=3\), outer \(\npoly=1.5\)) separated by a density discontinuity, run build_poly as follows:

$ $GYRE_DIR/bin/build_poly --n_poly=3,1.5 --z_b=1.4 --Delta_b=-0.5 --dz=0.01 poly.composite.h5

This model, written to the file poly.composite.h5, is visualized in the figure below.