Round a premium

Install Relativities and download the synthetic examples before running this page. This page rounds values with round(x, places, mode). RSL keeps every value exact until a round changes it. So the premium rounds exactly where the filing says, and only there.

Round to cents or dollars

round takes three parts: the value, the number of decimal places, and the mode.

            premium: Premium [cite: manual:p9] = round(self.coverage_a / 1000 * 3.125, 0, half_up)

2 rounds to cents, 0 to whole dollars, and -1 to tens of dollars.
The mode is required. Write the mode the filing states.
A value already on the target, such as 2.10 rounded to cents, stays the same in every mode.

Choose the mode

Mode	Rounds
`half_up`	to the nearest; a half goes away from zero
`half_down`	to the nearest; a half goes toward zero
`half_even`	to the nearest; a half goes to the even digit
`up`	away from zero
`down`	toward zero
`ceiling`	up, toward the larger number
`floor`	down, toward the smaller number

This rater rounds one amount to cents in each mode:

        step rounding [cite: manual:p9] {
            half_up: Premium [cite: manual:p9] = round(self.amount, 2, half_up),
            half_even: Num [cite: manual:p9] = round(self.amount, 2, half_even),
            half_down: Num [cite: manual:p9] = round(self.amount, 2, half_down),
            up: Num [cite: manual:p9] = round(self.amount, 2, up),
            down: Num [cite: manual:p9] = round(self.amount, 2, down),
            ceiling: Num [cite: manual:p9] = round(self.amount, 2, ceiling),
            floor: Num [cite: manual:p9] = round(self.amount, 2, floor)
        }

Rate 2.125, -2.125 and 2.121. The sample download includes this rater in relativities-examples/rsl/round-modes:

import json

import rslc

rater = rslc.PreparedRater("relativities-examples/rsl/round-modes")
for amount in [2.125, -2.125, 2.121]:
    print(amount, rater.rate(json.dumps({"Policy": {"amount": amount}})))
# 2.125 {"ok":true,"outputs":{"Policy":{"half_up":2.13,"half_even":2.12,"half_down":2.12,"up":2.13,"down":2.12,"ceiling":2.13,"floor":2.12}}}
# -2.125 {"ok":true,"outputs":{"Policy":{"half_up":-2.13,"half_even":-2.12,"half_down":-2.12,"up":-2.13,"down":-2.12,"ceiling":-2.12,"floor":-2.13}}}
# 2.121 {"ok":true,"outputs":{"Policy":{"half_up":2.12,"half_even":2.12,"half_down":2.12,"up":2.13,"down":2.12,"ceiling":2.13,"floor":2.12}}}

The modes differ on a half, such as 2.125, and on negative amounts.

Round the premium and cite the rule

Each premium the rater returns passes through a round. A premium with a step after its last round fails the check:

FAIL rater.rsl (strict)
error: E-OUTCOME-ROUND rater.rsl:22:13: rating outcome `premium` (Policy.premium) does not pass through an explicit round. State the filing's premium rounding rule with round(x, SCALE, MODE) and cite it, for example `round(x, 0, half_up)` for the nearest whole dollar or `round(x, 2, half_up)` for the nearest cent

The calculation that rounds the premium also cites the rounding rule, on the calculation itself. A citation on the whole step falls short:

FAIL rater.rsl (strict)
error: E-OUTCOME-ROUND rater.rsl:22:13: the round that produces rating outcome `premium` sits in `Policy.premium`, which has no attribute citation. A step citation does not name the rounding rule. Cite the filed rounding rule on the attribute itself: `premium: T [cite: source:region] = round(…)`

Write the citation after the type, before =, as the first example on this page does.

Round after each factor

Some filings multiply a chain of factors and round after each one. Write a product with by, to fix the order, and round_each:

            combined: Factor [cite: manual:p10] =
                product(self.factors as f by f.order, f.value, round_each: (4, half_up)),

The rater sorts the factors by order, multiplies them in turn, and rounds to 4 places after each step. Two factors of 1.00005 give 1.0002. One round at the end gives 1.0001. The sample download includes this rater in relativities-examples/rsl/round-stepwise:

rater = rslc.PreparedRater("relativities-examples/rsl/round-stepwise")
policy = {"Policy": {"base": 500, "factors": [{"order": 1, "value": 1.00005}, {"order": 2, "value": 1.00005}]}}
print(rater.rate(json.dumps(policy), detailed=True))
# {"ok":true,"outputs":{"Policy":{"factors":[{},{}],"combined":1.0002,"premium":500.1}}}

by names a number or date input of each element.
Each order value appears once. The rater refuses a repeat with INPUT-KEY on a keyed by list, and with INPUT-UNIQUE on other lists.
round_each works with sum and product.

Exact numbers explains why values stay exact until a round.
Citations lists each value that needs a citation.

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Comparative pricing

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Python reference

Data reference

Round to cents or dollars

Choose the mode

Round the premium and cite the rule

Round after each factor

​Round to cents or dollars

​Choose the mode

​Round the premium and cite the rule

​Round after each factor

​Related

Round to cents or dollars

Choose the mode

Round the premium and cite the rule

Round after each factor

Related