Rust crate and executable to transform light curve into dm–dt space, the implementation is based on papers Mahabal et al. 2011, Mahabal et al. 2017, Soraisam et al. 2020.
The executable dmdt can be installed by running cargo install light-curve-dmdt. You need rust toolchain to be
installed in your system, consider using you OS package manager or rustup utility.
Example of conditional probability dm–dt map plotting for linear dm grid [-1.5; 1.5) with 64 cells and logarithmic dt
grid [1; 100) with 96 cells:
sh
curl https://ztf.snad.space/dr4/csv/633207400004730 | # Get some ZTF data
tail +2 | # chomp CSV header
sed 's/,/ /g' | # replace commas with tabs
dmdt \
--max-abs-dm=1.5 --height=64 \
--min-lgdt=0 --max-lgdt=2 --width=96 \
--smear --approx-smearing \
--norm=lgdt --norm=max \
--output=example.png
dmdt --helpexpand
```text Plot dm-dt map from light curve
USAGE:
dmdt [FLAGS] [OPTIONS] --max-abs-dm
FLAGS:
--approx-smearing
speed up smearing using approximate error function
--help
Prints help information
-s, --smear
Produce dm-``smeared'' output using observation errors, which must be the third column of the input. Instead
of just adding some value to the lg(dt)-dm cell, the whole lg(dt) = const row is filled by normally
distributed dm-probabilities
-V, --version
Prints version information
OPTIONS:
-h, --height
number of dm cells, height of the output image [default: 128]
-w, --width <N lgdt>
number of lg(dt) cells, width of the output image [default: 128]
-i, --input <input>
Path of the input file, should be built of space-separated columns of time, magnitude and magnitude error
(required for --smare only). If '-' is given (the default), then the input is taken from the stdin [default:
-]
--max-abs-dm <max abs dm>
Maximum dm value, the considered dm interval would be [-max-abs-dm, +max-abs-dm)
--max-lgdt <max lgdt>
Right border of the lg(dt) grid, note that decimal logarithm is required, i.e. 2.0 input means 100.0 time
units
--min-lgdt <min lgdt>
Left border of the lg(dt) grid, note that decimal logarithm is required, i.e. -1.0 input means 0.1 time
units
-n, --norm <normalisation>...
Normalisation to do after dmdt map building. The order of operations is:1) build dmdt map, each dm-lgdt pair
brings a unity value to dmdt space;2) if --norm=lgdt, then divide each cell value by the total number of the
corresponding lgdt pairs, i.e. divide each cell of some column by the integral value in the column
(including values out of the interval of [-max_abs_dm; max_abs_dm)); 3) if --norm=max, then divide each cell
by the overall maximum value; 4) if any of --norm=lgdt or --norm=max is specified, then all values should be
in [0; 1] interval, so they are multiplied by 255 and casted to uint8 to make it possible to save dmdt map
as a PNG file. [possible values: lgdt, max]
-o, --output <output>
Path of the output PNG file. If '-' is given (the default), then outputs to the stdout [default: -]
```
```rust use lightcurvedmdt::{DmDt, Eps1Over1e3Erf}; use ndarray::Array1;
let dmdt = DmDt::fromlgdtdm_limits(0.0, 2.0, 96, 1.5, 64);
let t = Array1::linspace(0.0, 100.0, 101); let m = t.mapv(|x| 2.0 * f64::sin(x)); let err2 = Array1::ones(t.len()) * 0.01;
let prob = dmdt.condprob::