# symsolve v3.2.3

**Mercurial revision 5786:5c8b45563631 | 2026-08-04**

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## Description

`symsolve` is a tool designed to **compute the product of two matrices** using **sparse matrix representations** to reduce RAM usage. 

> **⚠️ Warning:** This tool is **not parallelized** yet.

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## Usage

```bash
symsolve [OPTIONS]
```

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## Options

| Option | Description |
|--------|-------------|
| `-h`, `--help` | Display this help message and exit. |
| `-m <file>` | Path to the ASCII file containing the **matrix to solve**. |
| `-r <file>` | Path to the ASCII file containing the **right-hand side (RHS) vector**. |
| `-o <file>` | Path to the **output file** where the solution will be saved. Default: `toto.dat`. |

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## Examples

### **Basic Usage**
Compute the product of a matrix and a RHS vector, saving the result to the default output file:
```bash
symsolve -m matrix.dat -r rhs.dat
```

### **Custom Output File**
Specify a custom output file:
```bash
symsolve -m matrix.dat -r rhs.dat -o solution.dat
```

### **Help Message**
Display the help message:
```bash
symsolve -h
# or
symsolve --help
```

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## Environment Variables

This tool does **not** use any environment variables for configuration. It relies solely on command-line arguments.

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## Notes

1. **Input Files:**
   - Both the matrix (`-m`) and RHS (`-r`) files **must** be provided in **ASCII format**.
   - The matrix file should contain entries in the format: `<row> <column> <value>`.
   - The RHS file should contain a list of values, one per line.

2. **Output:**
   - If no output file is specified (`-o`), the result is saved to `toto.dat` by default.
   - The output file contains the solution vector, with one value per line.

3. **Performance:**
   - The tool uses **sparse matrix storage** to optimize memory usage.
   - Currently, **no parallelization** is implemented. Performance may be limited for very large matrices.

4. **Error Handling:**
   - If either the matrix or RHS file is missing, the tool will display an error message and exit.

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## See Also

- [Sparse Matrix Storage Formats](https://en.wikipedia.org/wiki/Sparse_matrix)
- [BLAS (Basic Linear Algebra Subprograms)](https://www.netlib.org/blas/)
- [LAPACK](http://www.netlib.org/lapack/) (for linear algebra routines)