use num_complex::Complex64;
use runmat_builtins::{
BuiltinCompletionPolicy, BuiltinDescriptor, BuiltinErrorDescriptor, BuiltinOutputMode,
BuiltinParamArity, BuiltinParamDescriptor, BuiltinParamType, BuiltinSignatureDescriptor,
Tensor, Value,
};
use runmat_macros::runtime_builtin;
use crate::builtins::common::spec::{
BroadcastSemantics, BuiltinFusionSpec, BuiltinGpuSpec, ConstantStrategy, GpuOpKind,
ReductionNaN, ResidencyPolicy, ShapeRequirements,
};
use crate::builtins::control::tf_model::{
control_error, output_complex_column, polynomial_roots, ss_poles_from_object, TfModel, EPS,
SS_CLASS, TF_CLASS,
};
use crate::builtins::control::type_resolvers::damp_type;
use crate::{dispatcher, BuiltinResult};
const BUILTIN_NAME: &str = "damp";
const DAMP_PARAM_WN: BuiltinParamDescriptor = BuiltinParamDescriptor {
name: "wn",
ty: BuiltinParamType::NumericArray,
arity: BuiltinParamArity::Required,
default: None,
description: "Natural frequencies as an N-by-1 column vector.",
};
const DAMP_PARAM_ZETA: BuiltinParamDescriptor = BuiltinParamDescriptor {
name: "zeta",
ty: BuiltinParamType::NumericArray,
arity: BuiltinParamArity::Required,
default: None,
description: "Damping ratios as an N-by-1 column vector.",
};
const DAMP_PARAM_P: BuiltinParamDescriptor = BuiltinParamDescriptor {
name: "p",
ty: BuiltinParamType::Any,
arity: BuiltinParamArity::Required,
default: None,
description: "Model poles as an N-by-1 real or complex column vector.",
};
const DAMP_OUTPUT_WN: [BuiltinParamDescriptor; 1] = [DAMP_PARAM_WN];
const DAMP_OUTPUT_WNZETA: [BuiltinParamDescriptor; 2] = [DAMP_PARAM_WN, DAMP_PARAM_ZETA];
const DAMP_OUTPUT_WNZETAP: [BuiltinParamDescriptor; 3] =
[DAMP_PARAM_WN, DAMP_PARAM_ZETA, DAMP_PARAM_P];
const DAMP_INPUTS: [BuiltinParamDescriptor; 1] = [BuiltinParamDescriptor {
name: "sys",
ty: BuiltinParamType::Any,
arity: BuiltinParamArity::Required,
default: None,
description: "SISO tf model or ss state-space model.",
}];
const DAMP_SIGNATURES: [BuiltinSignatureDescriptor; 3] = [
BuiltinSignatureDescriptor {
label: "wn = damp(sys)",
inputs: &DAMP_INPUTS,
outputs: &DAMP_OUTPUT_WN,
},
BuiltinSignatureDescriptor {
label: "[wn, zeta] = damp(sys)",
inputs: &DAMP_INPUTS,
outputs: &DAMP_OUTPUT_WNZETA,
},
BuiltinSignatureDescriptor {
label: "[wn, zeta, p] = damp(sys)",
inputs: &DAMP_INPUTS,
outputs: &DAMP_OUTPUT_WNZETAP,
},
];
const DAMP_ERRORS: [BuiltinErrorDescriptor; 4] = [
BuiltinErrorDescriptor {
code: "RM.DAMP.INVALID_MODEL",
identifier: Some("RunMat:damp:InvalidModel"),
when: "Input system is malformed or missing model metadata.",
message: "damp: invalid model",
},
BuiltinErrorDescriptor {
code: "RM.DAMP.UNSUPPORTED_MODEL",
identifier: Some("RunMat:damp:UnsupportedModel"),
when: "Model class is unsupported.",
message: "damp: unsupported model",
},
BuiltinErrorDescriptor {
code: "RM.DAMP.OUTPUT_COUNT",
identifier: Some("RunMat:damp:OutputCount"),
when: "More than three outputs are requested.",
message: "damp: too many output arguments",
},
BuiltinErrorDescriptor {
code: "RM.DAMP.INTERNAL",
identifier: Some("RunMat:damp:Internal"),
when: "Pole extraction or output construction failed.",
message: "damp: internal error",
},
];
pub const DAMP_DESCRIPTOR: BuiltinDescriptor = BuiltinDescriptor {
signatures: &DAMP_SIGNATURES,
output_mode: BuiltinOutputMode::ByRequestedOutputCount,
completion_policy: BuiltinCompletionPolicy::Public,
errors: &DAMP_ERRORS,
};
#[runmat_macros::register_gpu_spec(builtin_path = "crate::builtins::control::damp")]
pub const GPU_SPEC: BuiltinGpuSpec = BuiltinGpuSpec {
name: "damp",
op_kind: GpuOpKind::Custom("control-damping"),
supported_precisions: &[],
broadcast: BroadcastSemantics::None,
provider_hooks: &[],
constant_strategy: ConstantStrategy::InlineLiteral,
residency: ResidencyPolicy::GatherImmediately,
nan_mode: ReductionNaN::Include,
two_pass_threshold: None,
workgroup_size: None,
accepts_nan_mode: false,
notes: "damp computes pole-derived control metadata on the host.",
};
#[runmat_macros::register_fusion_spec(builtin_path = "crate::builtins::control::damp")]
pub const FUSION_SPEC: BuiltinFusionSpec = BuiltinFusionSpec {
name: "damp",
shape: ShapeRequirements::Any,
constant_strategy: ConstantStrategy::InlineLiteral,
elementwise: None,
reduction: None,
emits_nan: true,
notes: "damp is model analysis and is not fused.",
};
#[runtime_builtin(
name = "damp",
category = "control",
summary = "Return natural frequencies, damping ratios, and poles for control models.",
keywords = "damp,damping ratio,natural frequency,poles,control system,tf,ss",
type_resolver(damp_type),
descriptor(crate::builtins::control::damp::DAMP_DESCRIPTOR),
builtin_path = "crate::builtins::control::damp"
)]
async fn damp_builtin(sys: Value) -> BuiltinResult<Value> {
let eval = DampingEval::from_value(sys).await?;
match crate::output_count::current_output_count() {
Some(0) => Ok(Value::OutputList(Vec::new())),
Some(1) => Ok(Value::OutputList(vec![eval.wn_value()?])),
Some(2) => Ok(Value::OutputList(vec![
eval.wn_value()?,
eval.zeta_value()?,
])),
Some(3) => Ok(Value::OutputList(vec![
eval.wn_value()?,
eval.zeta_value()?,
eval.poles_value()?,
])),
Some(_) => Err(damp_error(
"RunMat:damp:OutputCount",
"damp: at most three outputs are supported",
)),
None => eval.wn_value(),
}
}
#[derive(Clone, Debug)]
struct DampingEval {
modes: Vec<DampingMode>,
}
#[derive(Clone, Copy, Debug)]
struct DampingMode {
pole: Complex64,
wn: f64,
zeta: f64,
}
impl DampingEval {
async fn from_value(value: Value) -> BuiltinResult<Self> {
let gathered = dispatcher::gather_if_needed_async(&value).await?;
match gathered {
Value::Object(object) if object.is_class(TF_CLASS) => {
let model = TfModel::from_value(Value::Object(object), BUILTIN_NAME)?;
let poles = polynomial_roots(&model.denominator, BUILTIN_NAME)?;
Ok(Self::from_poles(poles, model.sample_time))
}
Value::Object(object) if object.is_class(SS_CLASS) => {
let (poles, sample_time) = ss_poles_from_object(&object, BUILTIN_NAME)?;
Ok(Self::from_poles(poles, sample_time))
}
Value::Object(object) => Err(damp_error(
"RunMat:damp:UnsupportedModel",
format!(
"damp: unsupported model class '{}'; supported classes are tf and ss",
object.class_name
),
)),
other => Err(damp_error(
"RunMat:damp:InvalidModel",
format!("damp: expected a tf or ss object, got {other:?}"),
)),
}
}
fn from_poles(poles: Vec<Complex64>, sample_time: f64) -> Self {
let mut modes = poles
.into_iter()
.map(|pole| {
if sample_time > 0.0 && pole.norm() <= EPS {
return DampingMode {
pole,
wn: f64::INFINITY,
zeta: 1.0,
};
}
let equivalent = if sample_time > 0.0 {
pole.ln() / sample_time
} else {
pole
};
let wn = equivalent.norm();
let zeta = if wn <= EPS {
f64::NAN
} else {
-equivalent.re / wn
};
DampingMode { pole, wn, zeta }
})
.collect::<Vec<_>>();
modes.sort_by(compare_modes);
Self { modes }
}
fn wn_value(&self) -> BuiltinResult<Value> {
real_column(self.modes.iter().map(|mode| mode.wn).collect())
}
fn zeta_value(&self) -> BuiltinResult<Value> {
real_column(self.modes.iter().map(|mode| mode.zeta).collect())
}
fn poles_value(&self) -> BuiltinResult<Value> {
output_complex_column(
self.modes.iter().map(|mode| mode.pole).collect(),
BUILTIN_NAME,
)
}
}
fn compare_modes(lhs: &DampingMode, rhs: &DampingMode) -> std::cmp::Ordering {
lhs.wn
.total_cmp(&rhs.wn)
.then_with(|| lhs.zeta.total_cmp(&rhs.zeta))
.then_with(|| lhs.pole.re.total_cmp(&rhs.pole.re))
.then_with(|| lhs.pole.im.total_cmp(&rhs.pole.im))
}
fn real_column(data: Vec<f64>) -> BuiltinResult<Value> {
let rows = data.len();
Tensor::new(data, vec![rows, 1])
.map(Value::Tensor)
.map_err(|err| {
damp_error(
"RunMat:damp:Internal",
format!("damp: failed to build output tensor: {err}"),
)
})
}
fn damp_error(identifier: &'static str, message: impl Into<String>) -> crate::RuntimeError {
control_error(BUILTIN_NAME, identifier, message)
}
#[cfg(test)]
mod tests {
use super::*;
use futures::executor::block_on;
use runmat_builtins::ComplexTensor;
fn tf(numerator: Value, denominator: Value, rest: &[Value]) -> Value {
let mut args = vec![numerator, denominator];
args.extend_from_slice(rest);
block_on(crate::call_builtin_async("tf", &args)).expect("tf")
}
fn ss(a: Value, b: Value, c: Value, d: Value, rest: &[Value]) -> Value {
let mut args = vec![a, b, c, d];
args.extend_from_slice(rest);
block_on(crate::call_builtin_async("ss", &args)).expect("ss")
}
fn damp_outputs(sys: Value, count: usize) -> Vec<Value> {
let _guard = crate::output_count::push_output_count(Some(count));
let Value::OutputList(outputs) = block_on(damp_builtin(sys)).expect("damp") else {
panic!("expected output list");
};
outputs
}
fn tensor_data(value: &Value) -> &[f64] {
let Value::Tensor(tensor) = value else {
panic!("expected tensor, got {value:?}");
};
&tensor.data
}
#[test]
fn damp_descriptor_signatures_cover_multi_output_forms() {
let labels: Vec<&str> = DAMP_DESCRIPTOR
.signatures
.iter()
.map(|sig| sig.label)
.collect();
assert!(labels.contains(&"wn = damp(sys)"));
assert!(labels.contains(&"[wn, zeta] = damp(sys)"));
assert!(labels.contains(&"[wn, zeta, p] = damp(sys)"));
}
#[test]
fn damp_tf_second_order_returns_frequency_ratio_and_poles() {
let sys = tf(
Value::Num(1.0),
Value::Tensor(Tensor::new(vec![100.0, 50.0, 400.0], vec![1, 3]).unwrap()),
&[],
);
let outputs = damp_outputs(sys, 3);
let wn = tensor_data(&outputs[0]);
let zeta = tensor_data(&outputs[1]);
assert_eq!(wn.len(), 2);
assert_eq!(zeta.len(), 2);
for value in wn {
assert!((*value - 2.0).abs() < 1.0e-8);
}
for value in zeta {
assert!((*value - 0.125).abs() < 1.0e-8);
}
match &outputs[2] {
Value::ComplexTensor(poles) => {
assert_eq!(poles.shape, vec![2, 1]);
assert!(poles.data.iter().all(|(re, _)| (*re + 0.25).abs() < 1.0e-8));
assert!(poles
.data
.iter()
.any(|(_, im)| (*im - 1.984313483298443).abs() < 1.0e-8));
assert!(poles
.data
.iter()
.any(|(_, im)| (*im + 1.984313483298443).abs() < 1.0e-8));
}
other => panic!("expected complex poles, got {other:?}"),
}
}
#[test]
fn damp_tf_first_order_returns_real_pole() {
let sys = tf(
Value::Num(1.0),
Value::Tensor(Tensor::new(vec![1.0, 2.0], vec![1, 2]).unwrap()),
&[],
);
let outputs = damp_outputs(sys, 3);
assert!((tensor_data(&outputs[0])[0] - 2.0).abs() < 1.0e-12);
assert!((tensor_data(&outputs[1])[0] - 1.0).abs() < 1.0e-12);
assert_eq!(tensor_data(&outputs[2]), &[-2.0]);
}
#[test]
fn damp_discrete_tf_uses_log_equivalent_poles() {
let sys = tf(
Value::Num(1.0),
Value::Tensor(Tensor::new(vec![1.0, -0.5], vec![1, 2]).unwrap()),
&[Value::Num(0.1)],
);
let outputs = damp_outputs(sys, 3);
assert!((tensor_data(&outputs[0])[0] - 6.931471805599453).abs() < 1.0e-10);
assert!((tensor_data(&outputs[1])[0] - 1.0).abs() < 1.0e-12);
assert!((tensor_data(&outputs[2])[0] - 0.5).abs() < 1.0e-12);
}
#[test]
fn damp_discrete_zero_pole_reports_deadbeat_damping() {
let report = DampingEval::from_poles(vec![Complex64::new(0.0, 0.0)], 0.1);
assert_eq!(report.modes.len(), 1);
assert!(report.modes[0].wn.is_infinite());
assert_eq!(report.modes[0].zeta, 1.0);
}
#[test]
fn damp_ss_uses_state_matrix_eigenvalues() {
let sys = ss(
Value::Tensor(Tensor::new(vec![0.0, -4.0, 1.0, -0.5], vec![2, 2]).unwrap()),
Value::Tensor(Tensor::new(vec![0.0, 1.0], vec![2, 1]).unwrap()),
Value::Tensor(Tensor::new(vec![1.0, 0.0], vec![1, 2]).unwrap()),
Value::Num(0.0),
&[],
);
let outputs = damp_outputs(sys, 3);
for value in tensor_data(&outputs[0]) {
assert!((*value - 2.0).abs() < 1.0e-8);
}
for value in tensor_data(&outputs[1]) {
assert!((*value - 0.125).abs() < 1.0e-8);
}
assert!(
matches!(&outputs[2], Value::ComplexTensor(ComplexTensor { shape, .. }) if shape == &vec![2, 1])
);
}
#[test]
fn damp_rejects_more_than_three_outputs() {
let sys = tf(
Value::Num(1.0),
Value::Tensor(Tensor::new(vec![1.0, 2.0], vec![1, 2]).unwrap()),
&[],
);
let _guard = crate::output_count::push_output_count(Some(4));
let err = block_on(damp_builtin(sys)).expect_err("too many outputs should fail");
assert_eq!(err.identifier(), Some("RunMat:damp:OutputCount"));
}
}