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3.4 KiB
Markdown
88 lines
No EOL
3.4 KiB
Markdown
# bin/README.md
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This folder contains the C reference executable (`spa_cli`) and the JavaScript test harness (`test.js`) to compare your JS port of the NREL Solar Position Algorithm (SPA) against the original C implementation.
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## Prerequisites
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* **Node.js** (v14+) installed on your machine.
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* **C compiler** (e.g. `gcc`) supporting C99.
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## Files
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* `spa_cli.c` – C CLI wrapper to parse command-line arguments into the SPA structure and output Sunrise, Solar Noon, Sunset in `HH:MM:SS` format.
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* `spa.c`, `spa.h` – The NREL SPA reference source (download separately).
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* `test.js` – Node.js script that runs 10 diverse test cases through both `spa_cli` and your JS port (`getSpa`) and prints a side-by-side comparison.
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## Setup
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1. **Download the NREL SPA source**
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```bash
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cd bin
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curl -O https://midcdmz.nrel.gov/spa/spa.c
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curl -O https://midcdmz.nrel.gov/spa/spa.h
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```
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2. **Copy or create `spa_cli.c`**
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Place the `spa_cli.c` file (provided alongside this README) into this folder.
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3. **Compile the C executable**
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```bash
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gcc -std=c99 -O2 -o spa_cli spa.c spa_cli.c -lm
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```
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* **Do NOT** include `spa_tester.c` for this purpose. The custom `spa_cli.c` handles all required argument parsing and output.
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4. **Install Node.js dependencies**
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From the project root (one level up):
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```bash
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npm install
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```
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This ensures your JS port (`index.js` and `dist/spa.js`) is available.
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## Running the Tests
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Inside the `bin/` folder, execute:
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```bash
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node test.js
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```
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You should see a table with each city/date, and matching Sunrise, Solar Noon, and Sunset times from both the C reference and your JS implementation.
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Example output:
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```
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Location | Date | C Rise | JS Rise | C Noon | JS Noon | C Set | JS Set
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-----------------------------------------------------------------------------------
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New York Summer | 2025-06-21 | 05:25:03 | 05:25:03 | 12:57:56 | 12:57:56 | 20:30:35 | 20:30:35
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...
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```
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## Notes
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* If you update your JS port (`index.js`), rerun `node test.js` to verify that drift remains within a second.
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* Ensure `spa_cli` is executable (`chmod +x spa_cli`) and located in the same directory as `test.js`.
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## Results
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Results from my personal tests when comparing original C version to this JS version is below:
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```
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% node test.js
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Location | Date | C Rise | JS Rise | C Noon | JS Noon | C Set | JS Set
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-----------------------------------------------------------------------------------
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New York Summer | 2025-06-21 | 05:25:03 | 05:25:03 | 12:57:56 | 12:57:56 | 20:30:35 | 20:30:35
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New York Winter | 2025-12-21 | 07:16:41 | 07:16:41 | 11:54:19 | 11:54:19 | 16:31:56 | 16:31:56
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London Summer | 2025-06-21 | 04:43:07 | 04:43:07 | 13:02:22 | 13:02:22 | 21:21:37 | 21:21:37
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London Winter | 2025-12-21 | 08:03:52 | 08:03:52 | 11:58:42 | 11:58:42 | 15:53:32 | 15:53:32
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Tokyo Summer | 2025-06-21 | 04:25:52 | 04:25:52 | 11:43:00 | 11:43:00 | 19:00:22 | 19:00:22
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Sydney Winter | 2025-06-21 | 07:00:12 | 07:00:12 | 11:56:56 | 11:56:56 | 16:53:52 | 16:53:52
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Reykjavik Mids | 2025-06-21 | 02:55:10 | 02:55:10 | 13:29:38 | 13:29:38 | 00:03:54 | 00:03:54
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Cape Town Summer | 2025-12-21 | 05:31:55 | 05:31:55 | 12:44:28 | 12:44:28 | 19:57:01 | 19:57:01
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Quito Equinox | 2025-03-20 | 06:17:54 | 06:17:54 | 12:21:10 | 12:21:10 | 18:24:25 | 18:24:25
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Tromso Polar | 2025-12-21 | N/A | N/A | N/A | N/A | N/A | N/A
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``` |