use runmat_builtins::{
BuiltinCompletionPolicy, BuiltinDescriptor, BuiltinErrorDescriptor, BuiltinOutputMode,
BuiltinParamArity, BuiltinParamDescriptor, BuiltinParamType, BuiltinSignatureDescriptor,
ResolveContext, Type, Value,
};
use runmat_macros::runtime_builtin;
use crate::builtins::common::spec::{
BroadcastSemantics, BuiltinFusionSpec, BuiltinGpuSpec, ConstantStrategy, GpuOpKind,
ReductionNaN, ResidencyPolicy, ScalarType, ShapeRequirements,
};
use super::pp::{
build_pchip_pp, evaluate_pp, pp_to_value, query_points, series_from_values, Extrapolation,
};
use crate::{build_runtime_error, RuntimeError};
const NAME: &str = "pchip";
const PCHIP_OUTPUT_PP: [BuiltinParamDescriptor; 1] = [BuiltinParamDescriptor {
name: "pp",
ty: BuiltinParamType::Any,
arity: BuiltinParamArity::Required,
default: None,
description: "Piecewise-polynomial struct representation.",
}];
const PCHIP_OUTPUT_VALUES: [BuiltinParamDescriptor; 1] = [BuiltinParamDescriptor {
name: "Vq",
ty: BuiltinParamType::NumericArray,
arity: BuiltinParamArity::Required,
default: None,
description: "PCHIP-evaluated values at query points.",
}];
const PCHIP_INPUTS_X_Y: [BuiltinParamDescriptor; 2] = [
BuiltinParamDescriptor {
name: "X",
ty: BuiltinParamType::Any,
arity: BuiltinParamArity::Required,
default: None,
description: "Strictly increasing sample locations.",
},
BuiltinParamDescriptor {
name: "Y",
ty: BuiltinParamType::Any,
arity: BuiltinParamArity::Required,
default: None,
description: "Sample values.",
},
];
const PCHIP_INPUTS_X_Y_XQ: [BuiltinParamDescriptor; 3] = [
BuiltinParamDescriptor {
name: "X",
ty: BuiltinParamType::Any,
arity: BuiltinParamArity::Required,
default: None,
description: "Strictly increasing sample locations.",
},
BuiltinParamDescriptor {
name: "Y",
ty: BuiltinParamType::Any,
arity: BuiltinParamArity::Required,
default: None,
description: "Sample values.",
},
BuiltinParamDescriptor {
name: "Xq",
ty: BuiltinParamType::Any,
arity: BuiltinParamArity::Required,
default: None,
description: "Query points.",
},
];
const PCHIP_SIGNATURES: [BuiltinSignatureDescriptor; 2] = [
BuiltinSignatureDescriptor {
label: "pp = pchip(X, Y)",
inputs: &PCHIP_INPUTS_X_Y,
outputs: &PCHIP_OUTPUT_PP,
},
BuiltinSignatureDescriptor {
label: "Vq = pchip(X, Y, Xq)",
inputs: &PCHIP_INPUTS_X_Y_XQ,
outputs: &PCHIP_OUTPUT_VALUES,
},
];
const PCHIP_ERROR_INVALID_ARGUMENT: BuiltinErrorDescriptor = BuiltinErrorDescriptor {
code: "RM.PCHIP.INVALID_ARGUMENT",
identifier: Some("RunMat:pchip:InvalidArgument"),
when: "Argument count or interpolation option grammar is invalid.",
message: "pchip: invalid argument",
};
const PCHIP_ERROR_INVALID_INPUT: BuiltinErrorDescriptor = BuiltinErrorDescriptor {
code: "RM.PCHIP.INVALID_INPUT",
identifier: Some("RunMat:pchip:InvalidInput"),
when: "Sample/query inputs are invalid for PCHIP construction or evaluation.",
message: "pchip: invalid input",
};
const PCHIP_ERROR_INTERNAL: BuiltinErrorDescriptor = BuiltinErrorDescriptor {
code: "RM.PCHIP.INTERNAL",
identifier: Some("RunMat:pchip:Internal"),
when: "PCHIP coefficient generation or tensor assembly fails internally.",
message: "pchip: internal interpolation failure",
};
const PCHIP_ERRORS: [BuiltinErrorDescriptor; 3] = [
PCHIP_ERROR_INVALID_ARGUMENT,
PCHIP_ERROR_INVALID_INPUT,
PCHIP_ERROR_INTERNAL,
];
pub const PCHIP_DESCRIPTOR: BuiltinDescriptor = BuiltinDescriptor {
signatures: &PCHIP_SIGNATURES,
output_mode: BuiltinOutputMode::Fixed,
completion_policy: BuiltinCompletionPolicy::Public,
errors: &PCHIP_ERRORS,
};
fn pchip_error_with_message(
message: impl Into<String>,
error: &'static BuiltinErrorDescriptor,
) -> RuntimeError {
let mut builder = build_runtime_error(message).with_builtin(NAME);
if let Some(identifier) = error.identifier {
builder = builder.with_identifier(identifier);
}
builder.build()
}
fn pchip_invalid_argument(detail: impl AsRef<str>) -> RuntimeError {
pchip_error_with_message(
format!(
"{}: {}",
PCHIP_ERROR_INVALID_ARGUMENT.message,
detail.as_ref()
),
&PCHIP_ERROR_INVALID_ARGUMENT,
)
}
#[runmat_macros::register_gpu_spec(builtin_path = "crate::builtins::math::interpolation::pchip")]
pub const GPU_SPEC: BuiltinGpuSpec = BuiltinGpuSpec {
name: NAME,
op_kind: GpuOpKind::Custom("pchip"),
supported_precisions: &[ScalarType::F32, ScalarType::F64],
broadcast: BroadcastSemantics::Matlab,
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: "PCHIP coefficient construction and evaluation currently run on the CPU reference path after gathering GPU inputs.",
};
#[runmat_macros::register_fusion_spec(builtin_path = "crate::builtins::math::interpolation::pchip")]
pub const FUSION_SPEC: BuiltinFusionSpec = BuiltinFusionSpec {
name: NAME,
shape: ShapeRequirements::Any,
constant_strategy: ConstantStrategy::InlineLiteral,
elementwise: None,
reduction: None,
emits_nan: false,
notes: "PCHIP builds a piecewise-polynomial representation and is not fused.",
};
fn pchip_type(args: &[Type], _ctx: &ResolveContext) -> Type {
match args.len() {
0 | 1 => Type::Unknown,
2 => Type::Struct { known_fields: None },
_ => match args.get(2) {
Some(Type::Num | Type::Int | Type::Bool) => Type::Num,
Some(Type::Tensor { shape }) | Some(Type::Logical { shape }) => Type::Tensor {
shape: shape.clone(),
},
_ => Type::tensor(),
},
}
}
#[runtime_builtin(
name = "pchip",
category = "math/interpolation",
summary = "Construct or evaluate shape-preserving piecewise cubic Hermite interpolants.",
keywords = "pchip,shape preserving,cubic hermite,interpolation,ppval",
accel = "sink",
sink = true,
type_resolver(pchip_type),
descriptor(crate::builtins::math::interpolation::pchip::PCHIP_DESCRIPTOR),
builtin_path = "crate::builtins::math::interpolation::pchip"
)]
async fn pchip_builtin(x: Value, y: Value, rest: Vec<Value>) -> crate::BuiltinResult<Value> {
let series = series_from_values(x, y, NAME).await.map_err(|err| {
pchip_error_with_message(err.message().to_string(), &PCHIP_ERROR_INVALID_INPUT)
})?;
let pp = build_pchip_pp(&series, NAME).map_err(|err| {
pchip_error_with_message(err.message().to_string(), &PCHIP_ERROR_INTERNAL)
})?;
match rest.len() {
0 => pp_to_value(pp, NAME).map_err(|err| {
pchip_error_with_message(err.message().to_string(), &PCHIP_ERROR_INTERNAL)
}),
1 => {
let query = query_points(rest.into_iter().next().expect("query"), NAME)
.await
.map_err(|err| {
pchip_error_with_message(err.message().to_string(), &PCHIP_ERROR_INVALID_INPUT)
})?;
evaluate_pp(&pp, &query, &Extrapolation::Extrapolate, NAME).map_err(|err| {
pchip_error_with_message(err.message().to_string(), &PCHIP_ERROR_INTERNAL)
})
}
_ => Err(pchip_invalid_argument("too many input arguments")),
}
}
#[cfg(test)]
mod tests {
use super::*;
use futures::executor::block_on;
use runmat_builtins::Tensor;
fn row(values: &[f64]) -> Value {
Value::Tensor(Tensor::new(values.to_vec(), vec![1, values.len()]).expect("tensor"))
}
#[test]
fn pchip_three_arg_evaluates_monotone_data() {
let value = block_on(pchip_builtin(
row(&[1.0, 2.0, 3.0, 4.0]),
row(&[0.0, 1.0, 1.5, 1.75]),
vec![row(&[1.5, 2.5, 3.5])],
))
.expect("pchip");
let Value::Tensor(tensor) = value else {
panic!("expected tensor");
};
assert!(tensor.data.windows(2).all(|pair| pair[1] >= pair[0]));
}
#[test]
fn pchip_descriptor_signatures_cover_surface() {
let labels: Vec<&str> = PCHIP_DESCRIPTOR
.signatures
.iter()
.map(|signature| signature.label)
.collect();
assert!(labels.contains(&"pp = pchip(X, Y)"));
assert!(labels.contains(&"Vq = pchip(X, Y, Xq)"));
}
#[test]
fn pchip_descriptor_errors_have_stable_codes() {
let codes: Vec<&str> = PCHIP_DESCRIPTOR
.errors
.iter()
.map(|error| error.code)
.collect();
assert!(codes.contains(&"RM.PCHIP.INVALID_ARGUMENT"));
assert!(codes.contains(&"RM.PCHIP.INVALID_INPUT"));
assert!(codes.contains(&"RM.PCHIP.INTERNAL"));
}
#[test]
fn pchip_too_many_args_uses_stable_identifier() {
let err = block_on(pchip_builtin(
row(&[1.0, 2.0]),
row(&[1.0, 4.0]),
vec![Value::Num(1.5), Value::Num(2.5)],
))
.expect_err("expected pchip argument error");
assert_eq!(err.identifier(), PCHIP_ERROR_INVALID_ARGUMENT.identifier);
}
}