{
"title": "semilogx",
"category": "plotting",
"keywords": [
"semilogx",
"logarithmic x-axis",
"semilog plot",
"matlab semilogx",
"response curve"
],
"summary": "Plot data with a logarithmic x-axis for response curves, scaling analysis, and MATLAB `semilogx` workflows.",
"gpu_support": {
"elementwise": false,
"reduction": false,
"precisions": [
"single",
"double"
],
"broadcasting": "none",
"notes": "`semilogx` uses the shared `plot` rendering path and then marks the active axes as logarithmic on X."
},
"fusion": {
"elementwise": false,
"reduction": false,
"max_inputs": 2,
"constants": "inline"
},
"requires_feature": null,
"tested": {
"unit": "builtins::plotting::semilogx::tests"
},
"description": "`semilogx` creates the same line objects as `plot`, but configures the current axes to use a logarithmic x-axis. That makes it useful for response curves, magnitude plots, and data that spans orders of magnitude along X while still using familiar MATLAB `semilogx` call forms.",
"behaviors": [
"The builtin returns the same kind of numeric line handle as `plot`.",
"Only the x-axis is switched to log scale; the y-axis remains linear.",
"Axes log-mode state is subplot-local, so `semilogx` on one subplot does not force every axes in the figure into log mode.",
"Positive x-values are the meaningful domain for a logarithmic axis, even though the plotted line object still preserves the original data handle semantics."
],
"examples": [
{
"description": "Plot a frequency response with a logarithmic x-axis",
"input": "f = logspace(0, 4, 200);\nmag = 1 ./ sqrt(1 + (f / 200).^2);\nsemilogx(f, mag);"
},
{
"description": "Compare two responses on the same semilog x-axis",
"input": "f = logspace(0, 4, 200);\nh1 = semilogx(f, 1 ./ sqrt(1 + (f / 200).^2));\nset(h1, 'DisplayName', 'low-pass');\nhold on;\nh2 = semilogx(f, (f / 200) ./ sqrt(1 + (f / 200).^2));\nset(h2, 'DisplayName', 'high-pass');\nlegend;"
},
{
"description": "Verify the x-axis scale through handle/property workflows",
"input": "f = logspace(1, 3, 50);\nsemilogx(f, log10(f));\nax = gca;\nget(ax, 'XScale')",
"output": "ans =\n 'log'"
}
],
"links": [
{ "label": "plot", "url": "./plot" },
{ "label": "semilogy", "url": "./semilogy" },
{ "label": "loglog", "url": "./loglog" },
{ "label": "axis", "url": "./axis" }
],
"source": {
"label": "`crates/runmat-runtime/src/builtins/plotting/ops/semilogx.rs`",
"url": "https://github.com/runmat-org/runmat/blob/main/crates/runmat-runtime/src/builtins/plotting/ops/semilogx.rs"
}
}